Your CV should be communicating relevant information about you that will help you get the job. I can't see that computer games or MN will help you get any job. If it's an animal-related job then leave the dog agility on.
For the same reason as I would say to people don't clog up their cv with (for example) their Home Ec GCSE grade C (it's not remotely relevant to the job they're applying for and will not give them an advantage), I would also say don't clog it up with irrelevant personal information.
Is your CV easily 2 pages without an interests section?
I wouldn't for design/illustration tbh. It can be useful in some jobs but as above unless they're particularly relevant or interesting the leave it. If they ask you at interview you can talk about dog agility.
Sorry I see it's graphic design, so take dog agility off. If you have space left in the two sides of A4 your cv should normally be limited to, you're probably not giving enough information about the stuff that is relevant.
It is only 1 and a half pages including the one line of interests I have added. I have only just graduated after an almost 18 year gap as a SAHM so I haven't put much about my previous work as it is all too long ago and not relevant.
I agree with fraktious - no need for personal interests section, or keep it extremely brief. They will only bring the topic up in an interview if they get desperate. Otherwise, it won't make any difference one way or another.
I would never list my interests on my CV as they are not at all relevant to my job. (I work in HR and interests would be photography, interior design, and baking! DOH!). I would also never ever include my date of birth, marital status, or any education prior to university. (many people still include these items on their CV and they serve absolutely zero purpose except to entertain the reader of the CV and give them something to poke fun at!)