Yes, in this week's Silly Legal Challenge (though one that looks like it was actually filed a couple of months ago, and is only now being noticed), Rebellion is trying to get control of the word... well... Rebellion - no doubt helped by the fact that it has never , ever been used before .
The claim, laid out in this Google Doc , is that Stardock/Sins developers Ironclad are using the name without authorisation and in a way likely to confuse consumers - as evidenced by the shocking way they simply refer to their expansion pack as Rebellion instead of, presumably, Sins Of A Solar Empire: Rebellion: A Tribute To Bobby Bearing - and one YouTube description that accidentally said "The developers over at Rebellion" without making a single spelling mistake.
Reading through the document, this seems a very silly case. Rebellion is an incredibly generic word, and the realistic odds of anyone mistaking a UK games developer for a strategy game expansion pack seem... to be charitable... rather low. It smacks of back-covering trademark protection rather than anything else, and will hopefully be sorted out quietly in some polite, mutually beneficial deal - maybe Ironclad adding a note to its game saying "Not affiliated with Rebellion Developments" and Rebellion Developments in turn promising to never again make a game as bad as Rogue Warrior.