On a more serious note, I use pw-gen.
http://pwgen-win.sourceforge.net/It's free. Open source. And it spits out stuff like this:
*{g1AoHd"#a|CKU}'~sMZX5$g~C"mu._i?nv6V}#
aW{j1`~N}&KS/Hu37Y$(IN@1?1,T!~j>b4;lMt<|
Fvl*a4mu*TZy?BR/G8*8>Rk|N06%geCB[}5f5D$d
u6v.;CCH(5$yOL8Z`2:kIXyhSeSJoW6\`]:+Qo[+
7u`AXzT$gock^{)4:?xgIA{fCf'1>:itTkq]]T>G
R77zjQQm5+00TzWI*IJyNH_`Rhxb1po.A3(-v~fq
But if that busts your software or website, you can also use "simple" versions like this:
FV1AbKarhC3GvWXl8qo4Uu2BkXSUguuEdEGHgb4b
jHfQfqu5c20Mm67px9vsxd9IUwyntc7aeQYYHcU0
SQItOe4ENYsElnalkae0Eq7c3IyesIlRK1gxIYms
ztcgELJLHgHVVcsDB7HqP2a1NUiH0jnjPldEKbjx
ZZFE7uexc1dr4IqJDftnJFvx3tsxvA8T2wM08lNm
dZT5NXNSHBj9zNYh4bCQRkoUmsEgtQO7gdijoLgx
And if you tweak the settings, you can even come up with bitcoin looking passwords (limit the char set to base58check.)