A great underrated classic that still has populated servers 24/7. (You can check for players with the in-game server list, bots won't be shown.) TFC offers one-of-a-kind exciting fast paced gameplay with tons of tactics and ways of playing the game. Easy to get into and enjoy, hard to master. However, you're bound to have fun along the way.
Despite old age, the game has a timeless design with a completely customizable appearance; you can choose from many custom models, sprites, skins, textures etc. There are active community servers hosting many of thousands of custom maps total with official game modes like; Capture The Flag, Control point, Attack/Defend, Escort, Deathmatch as well as custom ones like King of the Hill, Hold or Score Ball etc.
If you're interested in skill jumping (with weapons) there are servers hosting maps made for conc-, grenade-, rocket- and pipe jumping. There are also a lot of movement skill maps where you can climb, bunnyhop, strafe, surf, ramp slide and even water glide (shark) on a few servers. Or if you just want to play some random fun maps and mess around, there's escape, puzzle, hide & seek, sniping, role-play, secret hunting, low gravity and so on. As for mods, there's NeoTF (which gives you extra abilities and buildables), AdminOP (Ent Mod, Radio Mod, Hook Mod) and others.
It's not just one of, but The
most popular online multiplayer game of all back in 1999 before CS took the crown. Nowadays, there are barely any FPS games that don't get boring after a few hours. TFC will have you keep coming back for more, time and time again. Without relying on achievements or item drops.