Ok after a bit of searching I found the name of the service I was remembering:
http://en.wikipedia.org/wiki/Sega_Channel
"Sega Channel was a project developed by Sega for the 16-bit Sega Genesis console. Starting in 1994, Sega Channel service was provided to the public by Time Warner Cable and TCI, which later was acquired by the old AT&T during its cable acquisition spree that formed AT&T Broadband.
For a monthly subscription fee (usually $14.95 depending on location), along with a $25 activation fee, the subscriber would get an adapter, which plugged into the Genesis cartridge slot, and was connected to their cable television connection. The service would provide them with unlimited access to 50 games, selectable through an on-screen menu, with new games appearing every month and later every 2 weeks. The games would be downloaded in about 1 minute and play just like the retail versions. These games were organized by genre, such as Action, Fighting, Adventure, and Family. Each month, there was a special theme with originally composed music, artwork and game categories.
Sega also ran several promotions through the service:
- Special "test drives" for up-and-coming titles were provided. In some, after a certain time limit (15 minutes), gameplay was terminated, and the player was returned to the menu. Other games had limited content; for example, Primal Rage had only two characters playable, and Sonic 3D Blast ended after completing the first stage.
- Special modifications of existing retail games were made for Sega Channel, the most popular of which was a special version of Earthworm Jim by Shiny Entertainment.
- Some games not released in the United States were exclusive to the service.
- Cheats and tips could be accessed on the service and appeared while the games were downloading.
- Throughout the service's life, contests were held, where players could win Arcade machines, projection TVs, BMX bikes, etc.
The service was also available in Canada, in some parts of the United Kingdom on certain cable services, in Chile on the defunct Metropolis cable company, and in Argentina on a national TCI branch, Cablevisión TCI. Also, In Australia on Austar and the now defunct Galaxy."
