Simple check-in form.

This form lets people select a username, choose a date, and check in. I used October users on the Habit Heroes page.

Right now, all it does is write to this page the selected user and date. The next step would be writing the information to a spreadsheet, either Excel or Google Sheets.

The advantage to using this kind of form is that it's a conventional WDC page (well, a WDC web page), so it's easy to link to in WDC--it doesn't take people off-site. Processing the information could be done on a personal Google Sheets page or, for example, on a DropBox page and using Excel.