This is one of the go-to ways to get a man talking. Make sure you're asking him about something he knows a lot about.
If you see him at a random party, say hi and ask him why he's there. Make sure to keep it casual, though. You don't want to come off as too interested.
If you find yourself in a crowded bar with him, you can casually comment about how packed it is.
As you know, guys don't get a lot of compliments. They're more used to giving compliments. This makes them receptive to anyone who praises them.
Ask him to tell you the time or to give you directions to where you want to go. This is one of the most casual ways to open a conversation.