DIYer Noëlle used a Vika Amon tabletop from IKEA, a trestle and some adapted curtain rods (both of which you can get at a hardware store) to create a sliding mechanism not unlike the one that folds your ironing board in and out. Now it's a low coffee table during the day, but can be folded up into a high dining table when needed:
It's actually a pretty quick and simple mod, but sure to save you some space and make the room feel more open by getting rid of the need for a separate table. Hit the link for more pictures.
Lift Coffee Table | IKEA Hacker