A couple of intriguing contests for hot startups close their application process at the end of the day Monday, April 12 — so act fast to get your company a chance to be heard at one of these entrepreneurial conclaves.

First up: a contest to win a chance to present at the second annual Startup 2010 conference, to be held in New York City on May 20. Winning entries compete for a $100,000 grand prize, including $25,000 cash and goodies including free office space, legal services, Web hosting and more. This year’s Startup conference has a “mobile” theme, so if your company’s in that space you may have an advantage here. The application will ask you loads of questions about your business model, customers, target market, the works.

Next: The day-long Startup Lessons Learned event, which takes place Friday, April 23 in San Francisco. This event’s all about lean startups and how to operate on a shoestring.

Sponsor IMVU, a 3-D online community, informs us they’re offering eight free scholarships to startup business owners to attend the conference, a $700 value for each winner. Entering this one’s easier — just email leanapplication@imvu.com with a 500-word description of your business, how you use lean startup methods, and how the scholarship will help you or your company. Applications need to reach IMVU by midnight, and they’ll announce winners on Friday.