Parallax produces chips that belong to the basic stamp family. These basic stamps are programmed with PBasic through a serial connection to your computer to respond how you want, similar to most microcontrollers in the way of the PIC or Motorola lines. However, unlike most microcontrollers, the basic stamps have their own onboard eeprom and clock, making them damned expensive but ideal for the beginning hobbyist.
Think of PBasic as a normal microcontroller language mixed up with Basic. The syntax to make two LEDs connected to pins 7 and 6 turn on, and then write a message on an LCD display at the set baud rate and pin would be:
{{{'{$STAMP BS2SX} 'test.bsx
high 6 high 7 ' Makes 6 and 7 high pause 1000
serout 15,$43FD,[12,4,14,"Hello World!"] ' serial out to pin, baudrate to send at and the characters to send low 6 ' turn off an LED}}}
It is very simple, but packs a good punch considering that it all runs on a little chip. A good way to get started in the world of programming hardware and software together.