I agree with the idea that even when you don't feel eager if you make yourself do a few miles you get into it and enjoy riding further. Another strategy is clean and tune up your bike(s), perhaps doing a few mods you have been toying with such as new tires, different bars or grips or new gear ratios, for example, and see how they change the ride. A clean bike, well lubed chain and everything functioning optimally can be such a joy to ride, especially if your ennui has let your bikes slide maintenance wise.