Activision's Atari 2600 Action Pack
To activate the 6507 symbolic debugger, run the file 2600EMU.EXE. Pitfall will come up with an additional Debug item on the menu bar. You can then single step through the code, change registers, generate interrupts, examine memory, and so on. Note that many features are disabled, it only runs Pitfall, and this is only available in the original Windows 3.1 version.
General Mills Cereals
A full version of this was included on the promotional CD-ROM of Asteroids distributed with boxes of General Mills cereals. (See trivia entry for Asteroids.)
The first two Atari 2600 Action Packs were originally released for Windows 3.1. Then they were updated and released for Windows 95. The final release of these two Packs individually contained three versions: Windows 3.1, Windows 95, and Macintosh.
Information also contributed by Robert Morgan