Its been a few years, but we had a stag with about 30 people arriving from all over the place.
You can get group rates from hotels, but usually from Calgary a package deal/group rate with a charter might work out better. But, not always.
Charter's taxes are quite high these days, not like the hayday of vegas in late 90's with the old $99 flights
Shop around when you have such a large group, book well in advance and definately don't wait thinking you'll find cheaper deals 2 weeks before you want to go
I don't know if its still the same, but obviously spearmint rhino is great, so is Olympic gardens, especially later like 2-4am. Just remember never ever ever go into the VIP room.
When you have a large group of guy the girls/doormen will try to convince you to go into the VIP room, never ever go.
Sometimes VIP room are ok, at Olympic Gardens me and a buddy got in for $100 USD for 1 hr with our 2 girls, got probably 5-10 free drinks as well thrown in. Was nice for the privacy.
So yeah, just make sure you shop around. Often large groups you'll find everyone is looking on their own and you'll end up only booking a smaller part of the whole group. I dont' know why this is, probably because everyone always thinks Vegas is still dirt cheap to get too. Certainly not the case anymore
BTW chartering a plane to vegas, just to give you an idea the last time I priced this with Westjet for a client, it was about $33,000 CAD each way. Mind you thats the full sized plane, but still even the lear jets executive rentals are way up there.
Good luck and have fun!