Ask HN: I need to make extra $20k for a mortgage balloon payment. Any advice?

I'm in a tight spot and need to figure out how I can make an extra $20,000 dollars for a balloon payment on my mortgage. It's been a rough year personally and this somehow slipped off my radar and it's become an urgent issue.

I'm very experienced web developer and I do mostly contract work and sell a few products. I have easily made $20k in a month several times before, but those months are unplanned, and I just happened to book a lot of work.

Does anyone have any advice about how I can book $20k in work this month? Or sell one of my existing products?

Some of my work:

https://duetapp.com

https://theanchorapp.com

http://getsoloapp.com

http://boulevardjs.com/examples

I also have lot's of client work, mostly startups and some enterprise customers, which I'm happy to share privately.