Do universities do short courses?

Say your doing your degree, is it possible to take upon another course? Such example would be a language short course, I'm not sure if this would be classed as a society.

My answer is going to be totally irrelevant but I wondered about these courses too, like could I do a programming course even if I'm doing a biology degree yada yada yada

Many courses will give you an element of free choice, where you can choose any module you like. Usually people stick to similar topics, but usually you can choose anything - but there will be timetable issues as it could clash with something you're more committed to.

Imperial doesn't they're inflexible biatches, well at least it's a worldwide known institute

Some universities do let you do this, either as part of your course, as an extra credit course, or as an evening class. Evening classes sadly you generally have to pay for, but they are often heavily discounted for students. For example, you can do a two term language course for £180 at my university. That's a lot to a student, but it is significantly cheaper than those run outside universities. My university has also started offering free extra credit courses, including languages. These are great, but go on your transcript, so have an attendance requirement and exam/essay, which you have to pass if you don't want a fail on the transcript. They're a really good way to do something a bit different if your prepared to put in a bit of extra work. Ask around at your university, and look on their website to see if they offer similar things.