Bit Tech just published a worklog of Magnus Persson's Weighted Companion PC mod that got its inspiration from Valve's Portal.
"When it comes to great new games, one of the first thoughts on anyone's mind is "POORTTAALL!!" The utterly tongue-in-cheek humour, the innovative gameplay and entertaining (sometimes vexing) level design are enough to make pretty much every gamer find something to love.
It's no wonder, then, that someone would build a tribute to the game. In fact, the real wonder is that it's taken so long for someone to really bother! Fortunately, our resident mod-god Magnus Persson (aka [WP@]Wolverine on our forums) took it upon himself to start the trend.
Enter: The Weighted Companion PC – a very tiny (20cm cube) tribute to one of the best games of 2007. "The pink heart melts the frozen soul of the lonely modder," Wolvie said."