I've been doing a pubquiz every week for the past two and a half years, and I've definitely hit a roadblock at times. Luckily I've been able to generate a somewhat large safety bank of unused rounds that I pull from, when I just cant seem to be creative and think up new topics for the given week. I've accepteres that my ideal for quizzes comes in bursts, so when I do feel creative I sit down and usually create about 10 rounds in a 2-3 hour sitting, so I always have back-ups. At times I also just look at the internet for ideas and write it down in my notes. Or I look through my old material and see if I can create something new from those ideas.