There are a bunch of meet-ups and city sports leagues you can get involved in that make it fairly easy. It really depends on your interests. I would say it is pretty difficult to make lasting friends with random people at a bar (although they are friendly and will strike up a conversation - depending on the part of the city you're in), but if you get involved in something that interests you (volunteer work, sports, game nights at a local brewery, etc.), I think you'll find it is somewhat easy. There are a bunch of unique and strange activities always popping up around Denver, so if you are committed to meeting people, you definitely will. I would just say - don't feel weird about it. Ask someone to hang out after that first meeting. Since there are so many new people in town, usually they are really receptive! If not - you wouldn't want to be their friend anyway!