The problem continues, and once again not only for me. While it wasn't terrible last night, it was still annoying, and it was happening in spades this morning with only six people logged onto the server. Definitely seems to get worse the longer the server is online if that tells us anything.

I'm not sure how much better I can describe the behavior, but I'll try. It's like I'm lagging, but I'm not. I can consistently ping the server and don't drop any packets. But when the problem starts, it's like a series of frames within a set simply gets 'skipped.' When it happens two or three times a round (last night), it's not so bad. When it happens every five seconds (this morning) it becomes a real pain. It only really affects aiming, because when the skipping happens it either adds or deletes additional movement to the mouse, making aiming very difficult and sometimes pretty much impossible when finer precision is required. But hey, who needs to aim in CS:S?

I wish I could help more. Let me know if I can.