A game that has been out for a while, but recently has had a huge graphical improvement, with nvidia cards paying dividens on it.
http://www.trackmanianations.com/indexUk.php
The game is a racing game its a free 250mb download, with nice graphics, a good single player mode, and a even better multiplayer mode.
http://www.trackmanianations.com/common/shot.php?image=Tmn01.jpg
Here are some screenshots 
Yea anybody who havn`t played this i suggest u give it a try.
The game is realy cool, u can build your own tracks with loopings and all this crazy stuff
And u can race online and get ranked, u can also race for your own Country to get the most points
Just phuckin awsome game is this so check it out yalllll!!!!!
Pz
İm from turkey and im 105. in turkey where are you from?
This game is great. Lot of different tracks, super fun arcade racing. Plus it is free! I like it because the only internet connect option I have is Satalite which sucks for most games because the delay, be this game only updates times every sec or so, it works on any type of internet connection. Try it out!!
downloaded it, and liked it a lot =).
but now i cant get online anymore =(. it says i have bad proxy config, which is very strange, since i havent changed a bit since yesterday =/.
I'm playing a lot too!
I think that the multiplayer system needs to be fixed in some way beacuse I see other players movements not smooth enough.
They need some kind of prediction stuff, I know they are using something like that in games like Quake or CS.
echhh... the dreaded Starforce strike again. I wish dev's would just give up on those guys and try a different flavor for once (SecuRom, etc.). I just avoid Starforce if at all possible as it's done a job on my gaming system. 
I found the trackmania series quite by accident. I was shopping for something to play and found the original trackmania with the suzuki jeeps and the ford escort mk1's - that was a truly brilliant game.
Then Sunrise came and now this.
I have to say as a user used tio the previous versions this was a step up in competitivness - i found it to be much harder but still alotta fun.
It's definitely weird that they included starforce in a free game. I can't help but wonder if it's active.
Still, it's a great free game otherwise. Last time I installed it I removed Starforce and it still ran fine. (IIRC) It's pure arcade fun.
skaccomatto, it has prediction code. You might be on a high ping server or have a connection problem.
I have "Trackmania United". I'm not sure whether it's earlier or later than this one, but it's a lot of fun. The track editor is really cool, and I like giving the cars paint jobs. The car they chose for the "American" desert highway tracks was a little unusual, because it looks more like an import to me, but other than that, I really don't have anything to complain about. It's a great way to kill a few hours.