Sounds like a fun hobby. I’d follow along, if for no other reason than to brush up on C and assembly programming.
But if I may ask:
1 - Can you be more specific about what these little devices can be used for, especially around the home for a hobbyist. I have no idea what value these would have, however miniscule.
2 - Are these free compilers/IDEs only Windows based, or are there good equivalents in the Linux world?
3 - Do these involve soldering and circuit board work?
Look here for some project ideas
http://hackaday.com/category/attiny-hacks/
It’s like asking what can you do with a computer?
The answer is, a zillion different things.
People manage to use Linux to program these chips.. I use
an old XP box on the bench to do it.. I use Linux to surf the web since it’s far safer than Win. I’m sure a google search would enlighten about using Linux with the Atmel processors. Also, try this link http://www.ladyada.net/learn/avr/
You can build a lot of projects on a solderless breadboard but I recommend learning some soldering skills. I have seen quite a few tiny85 projects done as point to point soldered projects without even a circuit board.