So... Am I allowed to create events which you just have fun? I was thinking of hosting a Fill Up the Bubble Weekly event where you get any manga page and remove the text and well, you know, fill up the bubble with yor own text! If so, which board should I post it on?

Long story short:

Am I allowed to host events with no prize and where should I create said event?

Yes. Jusmi did that with the weekly "challenge yourself" event. Although he did chose "winners" who got their work featured in an archive. You may think about doing something like that as well. But the answer is yes. (You may not have as many people participate though.)

u should make it probably in the eventДs board. http://forum.toribash.com/forumdisplay.php?f=37
but since yours not toribash related and got no price, it would fit better in the offtopic board i think.

Thanks guys

So it's not related to toribash so does it go to offtopic?

You will have more participants and less off-topic trolls if you have this in anime united instead:

http://forum.toribash.com/forumdisplay.php?f=535

Either in Anime United or Design Events.