Day 5. Wait, no Flash?
I find Flash content as annoying as anyone, but a couple of my frequently visited websites still rely on it. To get Flash to play on your Kindle Fire, you'll need to jump through some hoops.
First, download the latest Flash Player APK from this thread or via the official Adobe archives. As with the YouTube app before (see Day 4), I had to copy it over to the "Downloads" folder and run it using a file manager app. Next, go get either the Dolphin Browser or Opera Mobile from the Google Play Store. Once Dolphin or Opera is installed, Flash websites should work just fine.
Day 6. More productivity, more fun
Working a whole day with the device, typing emails, editing documents and playing music, I quickly learned a few tricks that made the Fire HD more productive and solved some initial quirks:
Caps lock: Just double-tap on the SHIFT key and it'll turn into the caps lock key!
Dropbox: Wherever I go, I'd like to have constant access to my Dropbox folder. Since the official app isn't available on the Amazon store, I had to download and install it by going to the Dropbox for Android page and installing manually (no root required!).
iTunes: I have a huge iTunes library that I'd like to access from my Kindle. I'm sure there are other ways, but I used the Amazon cloud to stream my entire iTunes library to the Kindle. Note that this works only for unprotected AAC and MP3 files. Here's what I did: Download the Amazon MP3 Downloader, click on the "Cloud player" icon on your desktop and select "Import Music" from the website. This will install the Music Importer, which will let you upload part or all of your iTunes library to the Amazon cloud.