Ask HN: What to work on?

I'm getting really tired of dreaming up cool ideas for apps, cranking out prototypes, and then finding there is zero interest. Here are my four best ideas for what to work on next. I don't know how to "validate" them beyond a landing page/adwords. Last time I attempted that, adwords banned my campaign immediately.

LongCal: Basically, a calendar that goes beyond the standard month/week/day view. Emphasis on long term thinking and planning. I made a very rough prototype here (click on logo to get some test data): http://humbit.com/longcal/

uTrim: A URL shortener for universities. The idea is to create trustworthy links that can only be created by people actually associated with a school. I already have a functioning app and if you don't have an .edu account you can at least check out the landing page : https://utr.im/

Vulgat Library: Helps businesses create an internal lending library (movies, books, games). I sold this to two game companies, so it's the only thing I feel has proven demand. But I'd have no idea how to find more customers. This is the landing page that adwords objected to: http://vulgat.com/

Business naming app: After all the naming debacles I've seen on HN, I think an app that generates names (and checks against .com registration and trademark) could be really useful. My big doubt is if anyone would pay for it.

Do any of these sound worthwhile? Maybe I should just suck it up and do 30x500...

Some feedback from someone who has been in the same position. Most projects seem to have little interest at first. Your job is to iterate on the value prop, customer needs, and messaging - ideally by talking to customers. Simply running ads does not give you feedback that you need: eg: is there no interest because people don't understand the product (for me, Vulgat provided me no insight), or is it that the value prop isn't clear. Talk to people - the end user/buyer/purchasing cycle/industry/vertical is vastly different for each of these products. Focus on a product you can directly access the users. IMHO

What is 30x500? I googled and it looks like some kind of class but I don't understand. What is 30 and what is 500?

I read through the first half of this book (link at end) and some of the ideas in it may help you. It talks about some specific examples of iterating through the validation cycle. I can't say that I've created a multi-million dollar business off of the ideas in it. But some of the specific steps that the author outlines just make sense once you read them. http://runninglean.co/

My advice would be to dream bigger. You can't be sure if anything will work, so why not take a shot at something big then? I don't see any of those ideas becoming large businesses.