You can say a number of things, at least in America.
"Gee, where did the time go? Thank you so much for a wonderful night, but I must get going; I have an early day tomorrow."
"Your hospitality has been outstanding, but I have to be on my way. I look forward to hosting you the next time."
"I am so sorry but the time got away from me and I have to get going. Thanks for a great night."
And if you are really good friends, try "Hey buddy, gotta bolt! I have an early one tomorrow. Thanks for a great night."