Pitfall: the Mayan Adventure is a side-scrolling action platformer. It's the forth game in the Pitfall series. It was developed by Activision in partnership with Redline games and published by Activision in 1994.
Little Computer People is an incredibly advanced life simulation game created in 1985 by Activision for the Commodore 64, ZX Spectrum, Atari ST and Apple II. An Amiga version was released in 1987.
Pitfall II: Lost Caverns is the sequel to the award-winning PItfall by David Crane and was developed and published by Activision in 1984 for 9 different platforms including Apple II, Commodore 64, Colecovision and Atari 5200.
Hunter is a 3D action adventure created by Paul Holmes and published by Activision in 1991 for the Amiga and Atari ST. It is considered the first successful example of "sandbox" video game based on free roaming in a 3d environment.
The Activision Decathlon, or simply Decathlon, is a sports simulation created by David Crane initially for the Atari 2600 and published in 1983. It was then ported to MSX, Colecovision, Atari 5200 and Commodore 64.