Window film! There are tons of decorative (and removable) window film options sold at home improvement stores and online (Amazon has a bunch). They very in how much light they block. I think one of the stained glass window films might be really pretty there since you have so much light streaming in, but there are lots of options. Good luck!

I second the window film suggestion, but was just thinking of one that has a tint.

This is a silly question, but you did play with the way those vertical blinds lay, right? I have a similar situation with my bedroom window, also a rental with vertical blinds. If I turn the blinds so that the edge that is on the room side is pointing away from my bed, the light is directed to the wall and not at my bed. It's easier to sleep with light reflected off the wall than coming directly at you through the spaces in the blinds.

IKEA has some new floor length carpets out that have a microsuede feel on one side, and blackout material on the other side. While you said you can't take the blinds down, you CAN install drapes over them with the proper curtain rod.

http://www.ikea.com/us/en/catalog/products/10144866

and

http://www.ikea.com/us/en/catalog/products/70164795

or

http://www.ikea.com/us/en/catalog/products/00157227

BB gun. 'Nuff said.

I recommend adding thick or thermal drapes. I was able to add some to our similar non-removable blind treatments with a tension rod.

is it an option for you to ask your neighbors to redirect the light (assuming its direction can be changed, which is maybe not the case)? they might not have any idea that it's a problem for you.

Until you can go shopping for the previous nicer suggestions, there's the old stand-by of heavy duty aluminum foil taped shiny side to the glass.

Following up on muro.lamer's comment: as your neighbors if they can replace their existing bulbs with ones that are less bright.

I'm reminded of this story: when I lived in DC about 8 years ago, I owned a rowhouse adjacent to crack house. My neighbors and their friends would smoke crack on the porch. To try to deter them, I installed a 150 watt bulb in my front porch lamp.

I woke up two days later and found that my neighbors had painted two sides of the glass porch lamp shade with black paint to deflect the light away from their porch, where they continued smoking their pipes.

So, if all else fails, black paint might resolve your problem.

Light blocking fabric on drapes will do the trick. Choosing this option will give you an opportunity to ask about color, fabric, and curtain rod ideas on apartmenttherapy!

You can place curtains over the blinds with blackout or dimout liner. You can also put a roller blind behind the vertical blinds.

Blackout curtains do an amazing job. I got mine from Target; they weren't too expensive.

I had the SAME exact problem, and let me tell you... I feel your pain. We tried everything! The window film still allowed for filtered light to come in, so it wasn't a solution for us. We installed vinyl roller shades (fortunately we got them for free on Craigslist). The room is now completely blacked-out. I do have curtains w/ lining, and I left the standard window blinds up mounting the vinyl roller blades in the inner most position within the window frame. My husband and I are sleeping sooo much better. Good luck!

https://www.buyriteblinds.com/product-list.php?pid=39

What about those eyeshields they give out in first class on airplanes? :)

Get a really deep curtain rod that will extend past the binds and some black out or really thick curtains. Hang the rod a good way above the blinds. The room will seem bigger and no more light problem.

I'd go with telling your neighbors to quit wasting electricity and annoying people. You might even have a local ordinance to back you up -- worth checking.

I had similar problem until I bought IKEA TUPPLUR curtains. The block the light very efficiently and cost $30 for two panels. Try it!

thank you all for the suggestions! i'm going to look into each one, but i'm liking the eye mask idea. so simple, but i never even thought of it.

(the first thing we did was ask them to install a dimmer light, but they need the bright light so their 90 million kids can play basketball until 2am.... )

A face mask would help you sleep, but your body might still need the complete darkness in order to produce a hormone called melatonin. Melatonin is "the hormone that keeps your body clock on a regular schedule, ensuring that you feel sleepy in the evening and stay asleep through the night."

I would suggest black out fabric. It blocks out light completely and is pretty cheap by the yard. You could easily hang it over the existing blinds.

I have the very same problem and blackout curtains didn't solve the problem as the light still crept in round the edges of the curtains, so I invested in some Go Anywhere Blinds (http://amzn.to/igRA8O - a UK product but you should be able to find something similar in the US). It's basically cut-to-size blackout fabric which you stick to your window with suckers. Easy to put up and take down - thoroughly recommended!

I had a similar problem but I went over and asked if they could turn it off some point in the evening. Problem solved.

You can install black out drapery on a rod above the doorway. Then you can open and close as you wish.

Black out film or black paint will prevent you from ever seeing out that window - how depressing!

Hang curtains with a blackout liner. Film with an non-black out curtain is a good too.

Here's a trick from my dorm and rental days: Sew buttonholes along the top of the curtain. You can unclip the hanging blinds and slip the curtain in. Just store the blinds flat (under a couch or bed works great) and clip back in when you're ready to move!

Back when I worked nights, I covered my large bedroom window with white paper from a art store, then aluminum foil over that. Might be too dark for your needs, and it can't be removed and reapplied easily so you lose the view as well as he light.

Failing that, heavy curtains.

If you don't want to hang heavy drapes you can buy black-out liner at most home fabric stores. It's really light weight and you could hang it behind the blinds.

I'm a nurse and I work the night shift, so I sleep with natural light coming in. I rent and have decent wood blinds that are horizontal, but they don't block out the light. I use an eyemask pretty successfully (I found a good soft one at bed bath & beyond that curves around the eyes so you don't have to keep it too tight on your face), and take melatonin to help adjust. I was just thinking of rigging up some black out curtains from ikea! Just been lazy... :) good luck!

I have that problem sometimes, too. The neighbors are caretakers for a developmentally disabled man who turns the yard light on sometimes without their knowledge. (Since three years ago, before we built the house, the lights -- 3 spots -- were aimed at the woods, I assume they were installed to watch the wildlife. Now, however, they shine directly at the largest window in the world which is covered by white sheers and white silk panels -- not so darkening.

So far, after asking the neighbors to turn the lights off a few times, they seem to catch it themselves. (All that snow glare reminds them, I guess!)

If that didn't do it, I'd get microfiber room darkening drapes -- or line my silk drapes with blackout liner. (Might do that anyhow, actually!)

Bali carries a blackout version of their cellular shades, with a variety of colors to choose from (see link below).With a well-fitted inside mount, a long swag that covers the edges of the shades will mostly take care of any light seepage. I also like livingonscreen's suggestion of the blackout fabric that sticks directly to the window.
http://www.baliblinds.com/Style.do?productLineId=59&styleId=156

Ask your neighbours to help you out. Helped for me with my neighbours' beaming Christmas lights.

LOL @ abcornwell

I used to work the graveyard shift and needed my room dark to sleep. I covered the window with two layers of white latex paint facing the street and two layers of black latex paint on the inside. It left the room completely dark and when I moved I just peeled the paint off. Because it was latex it came off the glass easily. My landlord thought I had put up white window shades and never said a word about it.