I am flying through magical forest where candy falls from the sky. I must suck up the candy with my vacuum breath and spit it at the evil bees. If I am very quick, I can suck up poison candy and spit that at the evil bees. I can also spit some bees at other bees. This isn't the result of eating some highly dubious mushrooms. This is the premise of Vacuum Magic (free), a throwback to the classic 2-D scrolling side shooters of the NES era.
You control a little pixie sort of character, and you emit a constant stream of vacuum breath, which you use to suck up candy of various sorts which falls from the sky and floats around you. The candy gives you points, and you must eat all the candy to clear the level. (Vacuum Magic is not approved by the American Dental Association.) Of course, there are enemies. Evil bees--and other creatures--swarm in to try to kill you. You can kill them by sucking one in and very quickly spitting it out, or by hitting them from above. There are also targets to spit food at, "super food" pills which give you a protective force field, timed "challenge" rounds, and boss fights.
Vacuum Magic's controls are simple--use the arrow keys to move up, down, forward, and back, and the space key to fire (if you have food in your mouth) or shift direction. This latter bit I found a bit confusing, as I'd change heading when I wanted to fire, and vice-versa. The rule is simple enough--if you have food, you spit it, if you don't have food, you change heading--but in a fast paced game where you're just mashing buttons madly, it's a pain. On the other hand, that's the kind of reflexes and control games like Vacuum Magic require and reward--and which I don't possess.
Vacuum Magic is free and open-source, and it is still being developed. While perfectly playable, there is a constant update of content and bug fixes, and the developer is quite responsive to requests on the forums. While not as polished and complete as other open-source games, such as Neverball, it is still a fun diversion, and it's free.
Note: Although the game runs under Vista, if you try running it under the default settings, it will enter full-screen mode and be unplayable. Before trying to run it under Vista, you must find the "vacuum.cfg" file (should be in your main user directory) and set the "Fullscreen" value to 0, using a simple text editor like Notepad.