The handle broke off my toilet a few weeks ago, right at that time when it's too late to go to the hardware store but too early to wait until the next day to fix it (my boyfriend and I are both night owls so are often up into the early morning.) Sticking our hands into the tank every time we needed to flush seemed . . . unappealing, so we rigged up a temporary solution that we happen to think is pretty great.
Using zip ties and a key ring we fashioned a pull chain toilet handle that not only works amazingly well, but has become a hilarious conversation piece when we have guests over.
The zip ties attach to the plastic piece that pulls the flapper (rubber stopper that closes the hole between the tank and the bowl) up, and then one of them goes through the hole that's meant for the handle. A key ring is attached on the outside to keep the zip tie from falling through and to give you something to grab. If you wanted to get really creative you could probably attach anything you could think of on this end, perhaps making it match your bathroom decor?
In the end it was simple, fast, and cheaply done with things we happened to have on hand. We'd like to think MacGyver would be proud.
(Oh, and a month later, we have yet to replace our "temporary" fix.)