Dates
1.	1231 long months MMDD	/^(0[13578]|1[02])([0-2]\d|3[01])/
2.	1130 short months MMDD	/^(0[469]|11)([0-2]\d|30)/
3.	0229 February MMDD	/^02[0-2]\d/
4.	1231 putting all together: MMDD date validator	/^(02[0-2]\d|(0[469]|11)([0-2]\d|30)|(0[13578]|1[02])([0-2]\d|3[01]))/
5.	31.01.2011 German date (DD.MM.YY) validator	/^([0-2]\d\.02|([0-2]\d|30)\.(0[469]|11)|([0-2]\d|3[01])\.(0[13578]|1[02]))\.\d+/
6.	2011-01-31 ISO 8601 date (YY-MM-DD) validator	/^\d+-(02-[0-2]\d|(0[469]|11)-([0-2]\d|30)|(0[13578]|1[02])-([0-2]\d|3[01]))/
7.	23:59 HH:MM 24 h clock validator	/^([01]\d|2[0-3]):[0-5]\d/
Other
8.	47001010000 Estonian SSN validator	/^[1-6]\d{2}(02[0-2]\d|(0[469]|11)([0-2]\d|30)|(0[13578]|1[02])([0-2]\d|3[01]))\d{4}/
9.	3 Integer check	/^\d+/

Notes

1. Regexps in this page dont have $ in end, because end of teststrings is reserved for explanatory text. For example, /^02[0-2]\d/ above should be /^02[0-2]\d$/ in real applications.
2. Copy whatever you want (from this page), but never accuse me ;)