Do I need permission to run a ladder/league site from the creators of the games I choose to host ladders for on the site?

Interesting question. This comes up in other contexts, such as Fantasy Football, as well. The answer can be somewhat complex you need to watch very carefully what you do and how you do it, and for this you should consult with a lawyer, but YES, you can have a league/ladder site, if you do it CORRECTLY. Part of doing it correctly is not using materials that are prepared from or derived from protected, copyright materials of the game owner. Likewise, your website needs to make it clear you are not endorsed by the the game owner. You can make reference of the game in a simple way (just by saying what it is) and be safe under the "nominative" fair use of trademark however, again, you must avoid using copyright material or looking as though you are endorsed. Now, all this being said, many major games ENCOURAGE independent ladders and leagues and have permissive licensing for, for example, game stores to run, for example, Magic the Gathering / Street Fighter game tournaments. So, YES, you can do this if you do it carefully, but the exact details are beyond the scope of this question. You need to have a relationship with an attorney to whom you can pay a small fee to double-check what you're putting up to make sure it falls within fair use and avoids the traps of endorsement, copyright violation, etc . . . Personally, I love random and ladders/leagues. I don't mean to discourage you, just to inform you that there is a RIGHT and WRONG way to do it, and you need to make sure you do it the right way! Consult!

The question here is really, can I use someone else's trademark (name, logo or slogan) or copyright (software) for my own project, whether it is profit making or not. The answer is, that unless it is fair use, i.e., falls within the fair use doctrine or public domain you must obtain the appropriate licensing. This will frequently consist of a trademark and copyright license. These are complex legal documents that must be negotiated.