ATtiny is a series of Atmel AVR microcontrollers. Small and somewhat lacking in I/O, but still quite powerful (20MHz System Clock, 20MIPS, 64MHz Fast Peripheral Clock). Ideal for small spaces, limited resources, or a tight budget.
- 10bit ADCs
- 8/16bit timer
All of these can be picked up in low quantities for under $5 apiece from various suppliers.