[feelingreyt]

Stormster,
In my honest opinion what you are doing to your son is terrible! How dare you?!?
Just kidding....
Seriously, it is fine to expect your son to entertain himself for 30 minutes in a safe enviroment. In fact, I think it's very healthy for him. He needs time to learn to play alone. There is nothing wrong with you expecting a few minutes to yourself to unwind and catch your breath from your days activities! Heck, we all need that!
I put H in his crib or his play stand thingy when I need a few minutes, or a shower, or whatever. He may not be 100% happy with it all the time, but hey, we do what we have to do!
Little E is lucky to have a mom as dedicated to him as you are. A few minutes alone is not going to harm him in any way. Trust me!

ETA: I have 3 children. With each of them I have used their crib as a place for them to hang out and play for short periods of time. It has never hendered their sleep patterns or caused any confusion. My kids are great sleepers!