Ones I share with other people:
∞ is infinity
09f911029d74e35bd84156c5635688c0 is a number that is illegal to possess in the US
28:06:42:12 is Darko's Constant
4:8:15:16:23:42 was a fun half-season show that I think is in its, what, 8th season?
Ones nobody else has gotten into yet:
4726340 is the Sun bug ID requesting Tail Call Optimization in the JVM
567-68-0515 is Richard Nixon's social security number, which is what you should give when anyone asks you for a social security number when it's none of their damn business
The lack of interest in Nixon's Constant surprises me: that one's been going around since he was President, if not before.
The next couple of numbers I want to add have been problematic: I'd like to add Chaitin's Constant Ω and the 5th Busy Beaver number Σ(5), but since the former is impossible to compute numerically and the latter would take an absurdly long time, I would have to represent them by their symbols, and you can't put uppercase Greek letters in your interests.
Anyway, if you've got any interesting numbers, feel free to share them.