Many players through the years have compiled highlight videos showcasing CTF talent among the community.  Here is a good example:

Psychodelic 2 by ent

and, perhaps the most iconic JKA vid:

Avalon by jabba

Here are some of the most interesting ones, including a few videos from JK2 (the prequel to JKA), some non-CTF JKA vids, and a few Quake 3 vids thrown in, since JKA inherits a lot from that engine.

teh's game vid collection