I've been doing interval training for a while (playing a random note then another and trying to guess the number of semi tones between them) and it's definitely helped my ear but I'm wondering what are other exercises I can do? Plus does anyone know a song, solo or lick that starts with m 2nd, 2nd, m 3rd, 3rd, 4th, tritone or 5th going down? Ones that go up are pretty easy to find but going down seems to be rarer.

hmmm...

god onlys knows - minor second
yesterday - major second
beethoven's fifth - major third

with a little help from my friends (chorus) - perfect 5th
good vibrations (bass line) - perfect 5th
billie jean (bass line) - perfect 4th
another perfect 4th - think of mozart's most famous melody (sorry i don't have the name
do it again - minor 3rd
national anthem - minor 3rd