One of the more fun activities that can be done by all age groups on a friday night is paintball. Many of the paintball centres offer drop in nights so an organized group is not always necessary.
In Calgary we have checked out:
4839 47th St. SE
Here is a money saving tip for anyone thinking of playing. Those paintballs are consumed really quickly so if you are a group considering buying the paintballs by the case as there is a substantial savings. Each case contains 4 bags of 500.
Worried about your clothing, I asked an employee about it and it turns out that the paintball contains a mixture with vegetable oil in it rather than straight paint.
The Rampage facility is quite large and fairly well organized. Also on site is a pro shop offering a wide selection of gear and customized clothing. Some of the paintball clothing really is quite funky!