I believe those can run some Mac OS 8 version, 9 and some early releases of OS X. With the exact model this can be fully clarified.
So yes! You can run many things.
If you have that many floppys it might be a good idea to get a USB floppy unit, and back up all that old goodies.
There are some utilities out there to use emulators and handle disk images in newer OS X releases (Leopard and Snow Leopard).
Google for vMac, Sheep Shaver and you will find details on how to get them, install them and manage old Mac data software in current OS X versions.
Also check here for good old games: http://www.macintoshgarden.org
Have fun!
With OS 9, you can run Marathon. If you're booted in OS X, you can download Aleph One to run Marathon. I think you can even run it on a brand new mac using Aleph One.
As for your classic games, you should be able to run some of them in OS 9 (some really old games might not work though). It just depends on the game.
* A-10 Cuba
* Marathon
* Spaceward Ho
* Dark Castle
* Nanosaur
* Harry the Handsome Executive
* Sim City 2000
* Sim Earth
* Sim Ant
* Sim Tower
* Dark Seed
* Secret of Monkey Island
* Duke Nukem
* Unreal Tournament
* Quake
* And many more
Go check out MacintoshGarden. If you aren't getting the iMac online download the games and copy them via USB.