Buttons are fun. I added one to the bottom of my PunBB, between the Jump to and the copyright. =)
Then for the heck of it, I added the quotes about Firefox too, since Joel's quote was what first convinced me to switch.
Edit: Screenshot (below)
If anyone wants the details, here's how you can modify your forums to add them:
CSpotkill's Mozilla Firefox Button PunBB Mini-Mod
1. Open footer.php and save a copy as footer.bak in case you make a mistake.
2. Search the file for "Powered by", it should be about three quarters down the page.
3. Copy the following:
<td style="text-align:right"> <a target="_blank" href="http://www.mozilla.org/products/firefox/" title="Get Firefox - Web Browsing Redefined"> <img src="http://www.mozilla.org/products/firefox/buttons/getfirefox_large3.png" width="178" height="60" border="0" alt="Get Firefox"></a> </td> <td style="text-align:left"> <dl id="quotes"> <dt>?<a target="_blank" href="http://www.mozillazine.org/talkback.html?article=4145"> ...nothing short of a revelatory experience</a>.?</dt> <dd><em>- Maximum PC</em></dd> <dt>?<a target="_blank" href="http://forbes.com/infoimaging/2004/02/04/cx_ah_0204tentech.html"> ...a breath of fresh air... Microsoft should be worried</a>.?</dt> <dd><em>- FORBES</em></dd></td>
4. Paste all the above code between the </td> and <td class="puntopright"> which should be located above the "Powered by" text.
5. Save footer.php and test it in Firefox ;)
Note: You may want to disable the Jump To box if your forum titles are very large.