Firstly I do have experience with PHPBB so these aren't just made up things.
Change the spambot countermeasure to a question. It's much easier for users and much harder for bots. Bots WILL get through the captcha you have, they did on my forum. The question I used is relevant to my game and simple that anyone could possibly get through it. (How many sides are on a cube)
You'll also want to add some tags that forums really quite honestly need. Here are the ones I have:
(format is usage and then replacement and then usage)
{SIMPLETEXT}
<center>{SIMPLETEXT}</center>
adasaf
[spoiler = "{INTTEXT}"]{TEXT}[/spoiler]<dl class="codebox"><dt><a href="javascript:void(0);" onclick="var el = this.parentNode.parentNode.getElementsByTagName('dd')[0]; var v = el.style.display != 'none'; el.style.display = v ? 'none' : 'block'; this.innerHTML = (v ? '[+]' : '[−]') + ' {INTTEXT}'; ">[+] {INTTEXT}</a></dt><dd style="display: none;">{TEXT}</dd></dl>
Hidden text: [spoiler="Title"]Hidden text[/spoiler]
{TEXT}
<span style="text-decoration: line-through;">{TEXT}</span>
strikethrough text
[youtube]{SIMPLETEXT}[/youtube]
<iframe width="420" height="315" src="http://www.youtube.com/embed/{SIMPLETEXT}?rel=0" frameborder="0" allowfullscreen></iframe>
(That's the stuff that comes after ?v=)
This next one is a little slow so I advise you make it admin only for showing off the game's soundtrack:
<object height="81" width="100%"><param name="movie" value="http://player.soundcloud.com/player.swf ... ram><param name="allowscriptaccess" value="always"></param><embed allowscriptaccess="always" height="81" src="http://player.soundcloud.com/player.swf?url={URL}&g=bb" type="application/x-shockwave-flash" width="100%"></embed></object>
https://www.phpbb.com/customise/db/style/neon_2/ this is a fantastic and simplistic theme if you're into that sort of thing.
Oh and if you need help with modding phpbb I've toyed with it a bit and made an account verification script for logging into games with, and a highscore board that displays the scores on a user's profile.
