Well you can look at plastic hidey houses called Pigloo's. Most pet stores have them but you can look on Amazon or Dr Fosters and Smith (just google that) and you can find a bunch. I know some people have used old bins and turned them upside down and cut an opening for houses. Just have to be created =)

Male guinea pigs are very active and have lots of personality. They're sweet and fun. But they do spray, like most male pets, so you might consider having it neutered.