5-methoxy-diisopropyltryptamine is one of the more obscure tryptamines that Alexander Shulgin synthesised in the 1980s. It is variously described as being LSD-esque, but with more tactile effects (like MDMA) and increased libido (hence the name foxy-methoxy). It is currently (2002) in a grey legal area in the US but illegal (class A) in the UK. It is quite widely available on the internet, as a google search will show.
Some acquaintances of mine recently acquired 1 gram of 5-MeO-DiPT from the US. Their first problem was how to weigh out the 6-15mg doses. This they achieved by dissolving the whole gram in a litre of vodka, and measuring out 1ml per mg, with a pippette. They described it as having a nauseous come-up, but that the high was better than MDMA or 2-CB (the other psychedelics they've tried). They took to calling it fiend, because of the nasty come-up, but still got through most of the bottle in a few weeks.
CH3
/
O
\
C----CH
// \\
CH CH
\ /
C====C
| \
| NH
| /
C----C
/
CH2
\
CH2 CH2
\ /
CH--N
/ \
CH2 CH--CH2
/
CH2