I've posted a project giving example code for all the goodies on a Sure Electronics AVRDEM 2 board (about $26, shipping paid, if you watch eBay).
That includes a USART, switches, LEDs, speaker, 7 segment LED display, LCD, and interrupt driven TWI interface to an LM75 temperature sensor and external EEPROM. I also threw in some virtual timer support (up to 10, 0.01 second resolution, more or less) for good measure. The board uses USB and has a 12 MHz ATmega 16 and seems to be well made even with a couple of design shortcomings.
There's a 12 page pdf which has a discussion of the board and code, plus all the source code. The code is split out into separate source files by peripheral and is well commented. It's ImageCraft C but should be easy to port.
Any comments or suggestions are welcome and appreciated - this is the place to deposit them. Since it's demo code I realize there are better ways to do some of the things, but I'm always up for learning new tricks.
[Chuck - hope you don't mind - I added a picture as I thought others, like me, would like to know what this board looks like - Cliff]