I played a ton of LMCTF too. The offhand grapple was such a game changer in terms of speeding across maps. The LMCTF community was also great: hours spent on IRC, competitive ladders, forums (nachos), etc. It was a great time to be into online games.
Alliance for q3 was also great too, but it wasnt quite the same.
There is a Facebook community alive for LMCTF. Last time I checked they have a few servers online and organize pick up games.
We had a thing in university where most of the research staff would do a few rounds of Quake 2 death match around the end of the afternoon. We were all on the same local network; so ping times were great. The same levels over and over again. Great fun. And very satisfying to hear the groans of agony after a rail gun blast.
I played the hell out of the LMCTF mod back in the old days. Great times.