Standard Millennium timings are first games atart around 8.00 or 8.30am, last games scheduled for around 6.00 but have been known to run much later depending on factors like the weather (like in Amsterdam!)
Teams will play either Friday morning & Saturday afternoon, or Friday afternoon & Saturday morning so everyone gets an early morning & a day they can lie in. The schedule usually isn't ready until the day before to allow for teams that drop out at the last minute (this does happen surprisingly often) so you would have to assume you could be playing at any time if you're talking about time off work/school etc.
Teams get the chance to walk the fields on Thursday afternoon, & if you're playing I very strongly recommend this!
Semis are held Sunday morning, & the finals in the afternoon.