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I don't know about any hack but you can use a service like ogr3.com
This is how it works:
1 - create a link in your cbb post template to ogr3.com/yourtaghere, you can use your site name has the tag, tag only allows 33 characteres and a-z A-Z 1-9 and _
2 - Give a descriptive name to that link like: VOTE UP
3 - When someone clicks on the voteup link it will insert a record of that entry on ogr3.com/yourtaghere
4 - Ogr3 will display the top pages on the last 3 minutes, 3 hours and 3 days.
5 - Ogr3 has rss feed for each tag, you can use an rss reader module to grab the top threads of your tag and display it on a block, this way users do not have to visit ogr3 to see the top threads.
6 - Be aware that other sites may share the same tag, and results for other sites are counted. Choose a unique tag and you should be fine.
Look at this example
http://ogr3.com/xoopsOnce you click this link you should see this very page in the top list along with other xoops related news