My residential internet experience has always been poor, so when I started observing bizarre network behavior a few months back I attributed it to upstream problems and wrote it off with a sigh. The issue persisted however, so over the winter break I decided to sit down and tackle it once and for all.
Tracking down the source of the issue was an interesting adventure, and ultimately the problem was in the last place I thought to check: a pair of TEG-S80g unmanaged gigabit switches made by TRENDnet.
Do not buy! :)