Waking up in the morning can be a painful experience, but research seems to indicate that using light instead of sound will wake you up more pleasantly. There haven't been that many light-based alarm clocks, and the Philips Wake Up Light was one of the most effective and popular ones available. Here are some alternatives, including some that will require some hacking.
1. Sunrise Alarm Clock: Holly Hudson from NYC Resistor built an analogue to the Philips Wake Up Light and it looks like a good, DIY, alternative. An Adafruit Monocrhom clock keeps track of the time and activates a RGB LED light strip when it's time to wake up. It starts up with a dim blue light which increase in intensity before triggering a regular, bright floor lamp. That ensures that you wake up. If you're paranoid about missing your alarm and sleeping through it, you can always program a backup alarm on your phone.
2. Mad Catz AmBX Cyborg Gaming Lights: These lights are supposed to add an "Ambilight" feel to your computer workstation, and they be used in many different ways. With any computer, programming these lights to wake you up is feasible. Simply work through a music player and a task scheduler and you'll be able to make it work.
3. Programmable Sockets: While this won't be the most elegant solutions, hooking up a couple of lamps to a programmable power strip or light switch timer will allow you to test how much light you need to wake up. The testing is probably best done on the weekend, and staggering the lights within a couple of minutes, say 15-25, should do the trick.
4. Philips Wake Up Light: An alternative to the Wake Up Light is another Wake Up Light? Yes, because the original Wake Up Light was expensive, but these days, you can find a version for a lot cheaper. The HF3470 retails for $99.99 but it can be found online for as low as $67.
5. LIFX Smartbulb: Although this is still only a prototype, controlling an LED light bulb through your smartphone offers a wealth of possibilities. You can program a light-based alarm that will use any lamp to wake you up gradually.