I gave a webinar for CGIAR's Platform for Big Data in Agriculture where I talked about what ODK is, shared a little about the project’s impact, demoed the latest features in Collect and Central, and took a few questions from participants.
The webinar was recorded and I've linked to it below.
The demo is 15 minutes long and touches on a lot, including:
- Scanning barcodes to configure devices
- Audit logs with timestamps and geopoints of each action
- Toggling languages in the form
- Navigating with swipes and Next/Back buttons
- Using previous answers in question text
- Live-updating multiple questions per screen
- Playing offline videos as part of the form
- Likert questions with custom images
- Collecting polygons by placing points manually or automatically
- Calculating polygon area in the form
- Formatting the color of question text
- Built-in audio recording of the interview
- Filtering a long list of selects with autocomplete
- Composing a custom text message or email
- Remembering previous answers with last-saved as a dynamic default
- Viewing previous submissions on a device map
- Adding offline basemaps and layers on device
- Automatic form updates and submission sending
- Projects to group who can manage forms and view data
- Form updates and changes with no restrictions
- Filling out forms in a web browser
- Using public access web links for self-report
- Live dashboarding with PowerBI or R
If webinars like these are useful, please 
this post. If we get a lot of hearts, I'll schedule another webinar early next year to demo more features and take questions from the community.