1. What everyone else said + you need to be at the right place at the right time. Use J2o's GIP or Jazztool to see how many ppl are in a server. Also, always join when the server name says Anniversary Bash 7.

2. Lag. When ppl go really fast they are either warping (you can see ppl's warp-"trails" in MP or you're lagging badly. Ppl can reach real super speeds if they go into fast suckertubes or run (in the right direction ) on a really fast belt.