I found a great article (and explanation) on quick and cheap usability testing. This was particularly useful for a website I am evaluating for a client.
Personally, I tend to gel with these relaxed approaches more than formal lab settings. Maybe its just me but I really don’t think people use the web like this (i.e., a focused lab setting) . In my opinion, modern browsing is often performed on the bus / train etc (via mobile), cafe’s / bar or in the lounge whilst watching TV – or something similar. The obvious benefit to these kind of techniques is they are cheap and quick to perform.