To All Guys - Best Thing a Girlfriend can do in a Boring Rut.....?

I am in a relationship for about a year and a half and I feel like my boyfriend and I are in a boring rut. We live together and we see each other everyday and the 'pion' is almost gone. Trust me, we are content to stay in this relationship and don't want to break up but I noticed that he has started to look at girls a lot in public and lost the need to give me attention as he once did when we were first dating. What can I do that is special that can liven up our relationship? Please no nasty, stupid comments....