Cover your trampoline springs with pool noodles. I was pinched in springs so often when I was a kid. This is safe and looks awesome. Now I just need a house with a garden to put my pool-noodled trampoline in.
The coffee table top is GONNA get ruined anyways! :) Repaint a coffee table with chalk board paint. Draw a road, game boards, self portraits, work out homework problems, or just let the kids go wild. It will keep them entertained for hours.