Dammit I should be working but instead I'm going to post this.
DH and I always bounced on the sofa as kids and allow our children to do so also. The sofa was new from Multiyork but the pleasure we've all derived from it has been well worth any (non-detectable) weakening of the springs.
Are there any other secret or "out" sofa bouncing families out there or will everyone think I'm a bad mother for this? I've noticed that avoiding sofa bouncing is given as an example of behaviour to be stamped out of them in several child behaviour books ("you may bounce on your trampoline, but not on our new sofa").
We now climb the arm of the armchair, arrange the cushions on the sofa, then practice our diving and other Olympic sports [dammit, document has now printed out, must do work]