Shoutbox

Uhh... just get some wood glue and apply a good amount to the broken leg, put it back in position, make sure there's weight on it, wipe off the excess glue with a wet rag, and hope nobody moves the table before the glue dries.

(This stuff is very strong when fully dried, even stronger than the wood itself)

For some added strength, you could drill a hole in the leg and a hole in the table and insert a dowel rod.

I'm no expert though; there's probably a better way...