If you like your invite apps dead-simple, check out Mobaganda. You don’t even have to log in. Just click on start, add the name, date & time, and location, and create an event. The site, which is built on the Google App Engine, generates a Webpage that you can e-mail out to all of your friends.

Once the recipients go to the URL they can RSVP, and you can keep track via RSS or by checking back at the unique URL, which lasts for 30 days. (One downside is that no two events can share the same name during that time period).

Here’s an invite page I made in about a minute for a fake TechCrunch party:

The site generates an e-mail address that can be used to contact everyone on the RSVP list. You can also keep track of the RSVPs through Google Reader:

Or as a widget on iGoogle:

Not that we need more ways to invite friends to parties (see Pingg, Socializr, MyPunchbowl, etc.). But Mobaganda does reduce the process to its bare essentials. (The UI sensibility reminds me of Presdo). It got started as a conversation between Web developer Jason Stirman and Twitter founder Evan Williams. the question they were pondering: Would it be possible to create a better Evite, without even requiring a signup or login?”

Stirman is the creator of OhDon’tForget, a Ruby-on-Rails app that lets you send yourself pre-set reminders via text message (Time picked it as one of its 50 Best Websites last year). Stirman plans on adding text reminders to Mogabanda using OhDon’tForget (when you RSVP, you will be able to add a cell number to get a reminder the day before the event). he is also thinking of ways to add notes, maps, and other features. But he wants to keep it as simple as possible. After all, it is supposed to be the anti-Evite.

I want you to stop what you are doing right now and go try Presdo. It is a deceptively simple online scheduling assistant that is a prime example of what a modern Web app should be. It only shows you what you need to see at the moment that you need to see it. And it understands what you want to do based on normal (and not-so-normal) English that you type in.

“We actually threw a lot away,” says founder Eric Ly, who previously was a co-founder of LinkedIn and its first chief technology officer. He wrote most of the code himself and bootsrapped the entire site with only $35,000 of his own money. “I left LinkedIn on a Friday, and started Presdo on Saturday,” he tells me. That was back in April, 2006. He had to develop his own natural-language algorithm to deal with events, times, and scheduling, and the words people use to describe those things. The whole site is built with Ruby on Rails, Ajax, and the LAMP stack.

The home page is a plain, Google-inspired box. But instead of typing in what you are looking for, you type in what you want to do and with who: “Coffee with Eric in SF,” “Movie with Nadia Fri night,” “Meeting with Henry at 2:30 pm.”

It then takes you to a page with pre-populated fields based on what you typed in: when, who, where, what. You can refine the details further on this page. If you typed in the person’s email in the first box, it appears in the “who” field. If you didn’t, you can enter it at this point.

Presdo lets you pick a location by searching through local listings on a Google map. You can pick one near you, near the person you are meeting, or in between. (It helps if you first register with your own email and location.)

Or you can look at a list view of nearby places instead.

Presdo guesses what day and time you meant and puts those in as well. But you can offer up alternative times and allow the other party to pick the best one or suggest their own.

When you are satisfied with what you have, you hit “Send Invite.” The other person gets an e-mail with the details and a link back to Presdo, where they can change the time or place. You can also add a message. All the messages back-and-forth are recorded on the event page.

Once everything is set, you can export the meeting to your calendar (Presdo supports Outlook, iCal, Google Calendar, and Yahoo Calendar).

Every time you schedule an event with a new person, Presdo remembers who they are for the next time. You can also use Presdo as a to-do list. There are some obvious features Ly needs to add, such as support for other forms of messaging beyond email including mobile text messaging and Twitter. But he is off to a good start. The service is free, and he hopes to eventually charge for premium subscriptions. You can try it out now, and tell us what you think in comments.