One of the finest games to be built on the Quake 1 / QuakeWorld platform, Team Fortress set the bar high for class-based fast-paced multiplayer FPS. Easy to pick up but difficult to master, Team Fortress quickly spawned what was at the time (mid-1990s) a thriving worldwide community of teams (known as clans), leagues, mapmakers and server managers. With nine classes to mix across a server of up to 32 players, the range of tactics that could be adopted was phenomenal, and the mapmaking community ensured that TF never lacked for a high quality set of standard maps that encouraged creativity and experimentation with strategy. At its height, TF was the most popular online mod for Quake, with more simultaneous players than for any other, holding this position for years. The endless gameplay variations, well-tuned class balance, and large community meant that even a casual game on a public server almost always guaranteed fun times. My personal favourite class was always as a sniper - which could be played for defence, but most entertainingly could be used as a fragile but high DPS offensive class. A skilled stealthy sniper could wreak havoc in an enemy base. The community evaporated in 1999, due to competition from the sequel TFC, and widespread cheating via hacks exploiting vulnerabilities in the now-ageing Quake engine. The sequels - TFC and the wildly successful TF2 - are not quite as fast-paced or have as long a learning curve. Nonetheless they inherit the same DNA and have built huge communities of fans as a result.