Update: This build is now live on Google Play.
When I built the Android version of Glassboard, I decided not to do anything specific for Android 4. Based on Google's stats, it looked like it would be a very long time before enough people were running ICS for it to make sense spending any time supporting it.
But Google has made some smart moves lately that should speed up the adoption of Android 4. I think it'll become the leading Android version much sooner than expected.
So I decided we needed to support ICS in Glassboard as soon as possible. Now, in fact.
If you're running ICS and would like to test drive a Glassboard build that takes advantage of ICS features like the ActionBar and hardware acceleration, you can download the APK here. If all goes well, this build will be uploaded to Google Play in a few days.
If you run into any problems with it, I hope you'll let me know by posting in my "Android Testers" board (you can join using the invitation code ckanq).
PS: This build still supports every version of Android from 2.2 upwards - it just takes advantage of ICS features when running on Android 4.