How can I quickly and accurately estimate the number of people attending an event or performance? [more inside]
posted by steeb2er on Jun 15, 2009 - 7 answers

How can I stop second guessing myself? [more inside]
posted by nitsuj on Jul 8, 2008 - 17 answers

How do you judge large horizontal or vertical distances visually, with no (or few) other objects around to compare as a reference? [more inside]
posted by brain cloud on Jan 16, 2008 - 14 answers