This is what Dustin has been doing a lot lately. We bought Owen a cedar playhouse for his birthday which has required a great deal more work than any of us anticipated! It still isn't done but Owen already loves it!
We rented an 18ft inflatable slide. As you can see in the photo it had been raining in the early part of the day but thankfully it stopped at 10am and the party was at 2pm so we were set! We did have to slide down a time or two with towels underneath us before the kiddos got on!