In a few situations, it's nice to be able to get a rep recalc "on demand." In the past, I've simply pinged Marc Gravell about this, but it would be good not to have to bother him.
As an example, this morning I received lots of "dodgy" votes early in the day. They were removed later on, but then that effectively meant that the other votes I'd received up until that point in the day (which hadn't been counted due to the rep limit) still didn't get counted. A quick rep recalc would (possibly? not sure) have sorted this out.
Given that this is an expensive operation, I'd expect a rate limit on this - once per day per user would be adequate, I'd imagine - but it would definitely be handy. I'm hoping it wouldn't take much to implement, given that the moderators already have that ability.