I like the use of mybb and the theme is nice the logo is decent and I love that I'm not overwhelmed with empty forums and I actually joined and can't wait to see what you going to do with the site to make it better
I would like to give you a few tips about the layout and styling of the website. First off, I would try and combine the "Hello Guest" menu and the main navigation together. Having the two separated doesn't sit well on the page.
However, I do like the use of colour throughout the website, especially how you have tied the colours from your logo into the style of the theme. I also like the amount of open space of the theme, it doesn't feel overly crowded. I personally don't like ad's on web pages (and I think not many people do either!!), I feel that it just clutters up the page.