Do you think I'm trying to trick you with Reverse Psychology? I mean, seriously now.
I finished up Portal yesterday. Then I turned around and got Sabrina going on it. The way certain parts of the game freaked her out was very entertaining. =D And since I turned in the last of my assignments earlier this morning, I've been revisiting the game myself in order to get certain achievements. Naturally this has led to finding certain parts and levels more entertaining than others.
There are turrets in the game that you have to disable using your portal gun and wits since you have no real weapons. Finding new ways to take them out is very amusing. That and all the things they say make me laugh. Just as I love the saying by GLaDOS when you enter that level. I was going to post it and changed my mind. It's more fun to hear it firsthand in the game. Yes that's a hint that you should play it.
Anyway, I may play it again later today. I still haven't tackled the advanced levels that I unlocked by beating the game. I've heard that they're a pain in the butt to defeat so that should be a fun challenge. That was my only regret about the game, it was pretty easy to beat, even the boss battle is a snap once you figure out the trick to it. It was still very enjoyable though.
Oh and if you're too poor to afford a new game right now... go and have fun playing with this online flash version of the game. Portal It's very amusing and fun for a two dimensional game.