A friend of mine went ahead and made this Facebook page for the Weighted Companion Cube. If you have yet to play the greatness of Portal you really should either grab the Orange Box or the game itself off Steam. Stop reading this and go play it now.
Portal has my vote for Game of the Year. I love the playfulness of the game, the humor, and the over-the-top gameplay. I'm also a big fan of short games. I love games I can finish in a couple sittings. I'd be fine if Portal was even shorter.
What's even better is that Valve has just touched the tip of the iceberg with Portal. A lot of Portal was just educating and selling the concept. It isn't till near the end of the training that you really get a sense of things such as 'flinging' and the mind-bending gymnastics nature of it, which is where the fun lies. I'm sure there are even more interesting mechanics that can be developed. I love the idea of integrating something like the bounce pads from Quake 3:Arena. Or having to break through into areas by generating enough force by flinging yourself vertically then horizontally.
Can't wait to see what happens next!