What are some good extra/super curricular activities I can do during Year 13

Is there still time to do extra/super curricular activities such as work experience, internships, placements etc. I’m year 13, and I didn’t do much in year 12. I think that puts me at a disadvantage as all my friends have done one or more of these. I’m stressing because I’m year 13 and the time to do many of those things was year 12, now I have to spend most of the time on studying and exams and don’t think I have time to do any extracurricular stuff. Is it very important, and if so where can I find easy, quick activities to put on my statement in year 13?

What do you intend to do after A Levels or your degree? There's little point in doing irrelevant extra curriculars.
The extra curriculars would also depend what is available in your surrounding area. As much as I would like to say you can get an internship at NASA or teach English in a third world country, it's not likely or practical if you live on the other side of the world.

Extra curriculars can help if it's relevant or strongly recommended for the course or job that you want to apply for. In particular, if it's for a very competitive course or job where they praise you on these extra curriculars. If they don't, then it's not important.

Without knowing the specifics, I am drawing a blank.

I'm thinking about computer science or mathematics at either Imperial College London or Cambridge if i get the grades. It would be good to do something quick and useful that I can write about to boost my application. I know computer science is competitive, but i don't think there is enough time until the deadline for Cambridge in October and for Imperial in December, for me to do work experience or placements since summer has passed.

The extra curricular that stands out would be the Maths Olympiad. I am not sure if you can still do this before the deadline.

For computer science, again not likely you would be able to do much, considering the deadline is next month. You're probably better off producing a portfolio of IT projects e.g. programmed an app or something.

As far as I know, the unis care more about your passion for the subjects as opposed to what extra curriculars that you have done. Unless their entry requirements specifically say that they are looking for a well rounded applicant who is engaged in all sorts (and the last time I've checked, nowhere on their pages does it say that for computer science or maths), then I think the better strategy would be to read as much as you can in computer science and maths. The side projects would be a bonus, but I don't think you would have enough time to do all of the above.

The key thing with Cambridge I think is to be able to perform well in the interview, assuming you get invited. You would need to be able to talk about your chosen subject at length. Feel free to get a second opinion from people who successfully applied to these courses.

Is there still time to do extra/super curricular activities such as work experience, internships, placements etc. I’m year 13, and I didn’t do much in year 12. I think that puts me at a disadvantage as all my friends have done one or more of these. I’m stressing because I’m year 13 and the time to do many of those things was year 12, now I have to spend most of the time on studying and exams and don’t think I have time to do any extracurricular stuff. Is it very important, and if so where can I find easy, quick activities to put on my statement in year 13?

I'm thinking about computer science or mathematics at either Imperial College London or Cambridge

Hi! A really simple way to get super curricular activities for your PS is by completing courses online that show you developing your interests. These can be quick and some are not too lengthy if you're short on time.
A good website is https://www.mooc.org/ for these. You could also listen to podcasts, read articles and even watching Ted Talks as these show you going outside of the curriculum to learn more about your subject.
Hope this helps

Look at the suggested extra reading etc on this list from Cambridge - good for all Unis : https://www.undergraduate.study.cam.ac.uk/sites/www.undergraduate.study.cam.ac.uk/files/publications/super-curricular_suggestions.pdf