The middle of semester can often be the time when one tends to enter a bit of a funk and get disheartened about (a lack of) research progress.
In the case that you need a bit of inspiration, you should definitely watch the following video:
This is a lecture by the late Dr Randy Pausch, of Carnegie Mellon University. Diagnosed with terminal cancer and given 6 months to live, Dr Pausch gave an amazingly inspirational speech on how to achieve your childhood dreams and to get past the 'brick wall' blocking your progress. Although watching the whole thing is a bit of a time investment (circa and hour), it is well worth it if you have the time (even if you don't, watching a bit of it can give you the flavour of what he is on about).
Usually I'm a bit sceptical of these kind of motivational speeches, but I found the lecture brilliantly compelling and inspiring. Especially given his circumstances, this is quite an exceptional lecture.