Spark got rebranded and recoded as a browser based game called "Armor Critical" because the owners thought it would help prospective players be able to try out the game faster. It works just as well now on full screen in the browser as it did with the spark or arc clients, although there are some major bugs that need to get worked out. Since in my opinion it's still the greatest game ever, and the bugs don't usually affect the gameplay, they're not a big deal for me. If you try out the game, you'll want to make sure you have your browser and Java fully updated (do it manually just to be sure) and someone in the lobby might have to help you if you're having trouble getting into your first game. After you figure out that first game though you won't have any more problems. On AC (armor critical) I use the name "Fuse" so if you see me around give me a holler (or a PM). The URL to the new website is: http://armorcritical.com/
Hope you enjoy!
Wow! That is great news! I thought the game was completely gone!