Yeah, it would be pretty cool to make Mario or Link, blocky 8-bit style.
Or how about Sonic the Hedgehog's head? That would take some skill to do.
Reminds me of a project in Spanish 1 back in high school when we were making pinatas. This was when Attack of the Clones was in theaters, I believe, so a couple guys made a 2-foot Yoda pinata, full body, complete with cloak and lightsaber. It was pretty epic. Then they made a Darth Maul head and had Yoda beat it up with his "lightsaber". Awesome. You could try some sort of project like that with two of them. Not specifically suggesting Yoda and Darth Maul, but perhaps something like Mario and Bowser, Sonic and Robotnik, Link and Ganon, or something like that.
Or, having just come from the whole chess-puzzle incident thread, how about 10 chess pieces? You could be on your way to making a full set! That would be extra work, but a pretty cool project when you're done.