We're sure a nice DIY design could make for a really cool pop-up coffee table. Until now, we've only seen unsatisfying finished models like this or this. Here is an example of one pretty nice DIY pop-up design that's used as a side table plus storage.
Pop-up coffee tables are something we've seen around but we're never impressed with them aesthetically. What we do like, though, is the idea that one horizontal surface can function as a low coffee table and a dining or desk-height table in a small apartment. If you're handy, the mechanism for pop-up coffee tables can be purchased sans-table.