Themes and layout

What are the themes available for Community forums and is there anyway to demo or try it out before purchase? I really like what I have read so far but want to make sure this is the right fit. Being able to embed polls is a must and I want to make sure I have some control over the look and feel of what makes it on my pages. Can you change fonts, color schemes, add and subtract things from the polls layout, etc? And if you can't try it out before purchase are there any other sites to check out that using this? Thanks.