If you use Google Reader then sorry about the feed spam. The problem occurred since I switched servers to another one, and all my domains were mapped to the same IP/website for a few minutes which messed up the feeds on Spiked Math. I did fix the feed, however, in Google Reader those items will be permanently there (in cache) since Google doesn't remove anything after it's published :-(. I don't know about other feed readers, but the actual feed is fixed and has those items removed.
My sincerest apologies,