I have it on my iPhone. It's pretty fun, but I actually think Fantastic Contraption is better. The level design on Crayon Physics isn't that great, but the game engine is slick.

I already wasted enough time on fantasic contraption. I loved it.

You have a tablet? Which one do you have? Do you like it? I'm currently shopping for one and trying to figure out what's best. I just looked at a Fujitsu and an HP at Fry's but those are the only two they had. I still want to check out at least the Panasonic Toughbook and a Gateway. And a friend has a Lenovo ThinkPad she really likes. So many options but so few big ones :(

I have an old Toshiba m200-s383. I really love it, but it's old enough it's probably not of interest to you.

I think the best feature is that the pen can be detected with out touching the screen. I don't know if this is completely common with modern tablets. I haven't really looked at tablets that hard. I was just looking for a laptop and it turned out the tablet made a lot of sense.

Of the ones I tried so far the HP had that feature, the Fujitsu did not. I'm still not sure whether I would find it useful or annoying. Definitely seems like would contribute to screen life.

it means the pen works more like a mouse. I have an even older fujitsu that doesn't have that feature and it keeps trying to inturpet my pen movements as things, since it can only tell what's going on when you're touching the screen. On my toshiba I can use the pen and still do things like mouse overs, drags, etc.

Numpty Physics is a killer app for tablets. (It's basically Crayon Physics.)
It's primarily for the Nokia linux tablets, but it's open source
so I believe there's Windows and other Linux ports:

http://numptyphysics.garage.maemo.org/

I like crayon physics pretty well so far. I ran out of free levels though. I wonder if I should try any of the other games you mentioned.