Buying new workout clothes always motivates me to go to the gym! even if its just a new workout tank top! Also try going to a workout class instead of working out alone. I have a body pump class I attend on Wednesdays, and when I don't feel like going, I feel like I let the girls in my class down. Sometimes, I just have to tell myself "suck it up and just do it!" most of the time there isn't something serious thats keeping me from the gym, it's just me being lazy, so sometimes I just have to have a mental pep talk with myself, and just make myself go! and I always feel better afterwards.