The other day I was talking with a few colleagues about some of the less conventional apps we use on a day-to-day basis. Here are five that I've begun using regularly that you may not have heard of but are definitely worth checking out:

SoundGecko reads to you. If you ever come across a long article online that you want to read but never have time to get to, copy and paste the link into this app and SoundGecko will read it to you. This is great for long Atlantic or New Yorker pieces that I know I'll never get to -- you can listen while driving or walking around town. I've used it quite a bit over the last several weeks. Thanks to Michael Katz for the recommendation on this one.
Lift helps you create good habits. There's lots of research that suggests that habits are the secret to high performance -- it's just too hard to motivate yourself to do the hard stuff every day. You have to create good habits. Exercise has to be a habit like brushing your teeth is a habit. The Lift app helps you do that by allowing you to track and share your habits. Spark Capital invested in these guys a while back and Bijan Sabet wrote a good post on them that gives a good summary of how people use the product.
Amazon Instant Video is a no-brainer. If you're an Amazon Prime subscriber (if you're not, you should be) you get free access to Amazon Instant Video. Download the app -- it's comparable to Netflix, can be streamed to your television and is included with your Prime Subscription.
Cal is the best calendar app I've ever come across. The challenge I've always had with calendar apps is that they typically have terrible usability. They never seem to work nearly as well as desktop calendars. Cal has a fantastic look and feel and is super easy to navigate. It instantly syncs with your work and personal calendars. It even syncs your Facebook calendar and TripIt itineraries so everything is one place.
Refresh gives you the 411 on people that you meet. This one was recommended to me by a colleague and I have to caveat this in that I've only been using it for a few days. But so far I like what I see. Refresh integrates your calendar and social networks to create a quick snapshot of the people that you're meeting with. When you open that app you'll see a snapshot of your upcoming meetings and the people that will be attending those meetings. Refresh then aggregates a ton of information (mostly from social networks) into a "dossier" for each individual --where they've worked, where they went to school, what they Tweet about, what their interests are, etc. It's basically a more accessible and beefed up LinkedIn profile. I haven't been using it long enough to speak to its utility but it works well and has a slick design. If you have lots of external meetings with people you don't know a lot about it's worth checking out.