/tg/ Dice
Once upon a time some admin thought that it would be a good idea to give /tg/ a dicerolling mechanism. In practice it's mostly ignored, or it serves similar purpose as "first person to get doubles" threads, althoguh some enterprising fa/tg/uys have found good uses for them, and it used to be that good fun could be had at the expense of newfags that didn't know how to work the direroller properly. Because your results don't become visible until you post your comment, threads utilizing the feature can be a bit bloated. If you give /tg/ a random table to roll on, then each person responding will have to post once to roll, and once again to remark on their results. That said, it works well for things like the 40k faction generation tables.
TG dice is what fa/tg/uys call the strange phenomenon whereby /tg/'s random number generator tends to be anything but. The reason for this is that /tg/'s dice aren't truly random. Like most RNGs it's actually a pseudo-random generator tied to 4chan's server clock. The effect usually isn't that dramatic, but fatguys love to blame it for their shit rolls anyhow.