If you are a fan of productivity apps (like I am), there are a whole lot of options out there. Sometimes, however, I've found a lot of apps to be cluttered and busy—an app that was originally meant to keep my to-dos organized just ends up giving me a headache. Maybe you just want something clean and minimalist that specializes in one specific task. We won't get into which productivity apps have the most features, but here are some apps that may give you some peace of mind with their efficient and simplistic design aesthetic.
Brought to you by swissmiss and Fictive Kin, TeuxDeux has a snazzy minimalist design for those that like making to-do lists (I don't know about you, but I'm really digging the clean fonts and white/red/black color cheme). You can use TeuxDeux's free browser-based app while at home or work and sync your lists with your iPhone. TeuxDeux also allows for multiple accounts so you can share your lists with others (miscellaneous to-dos, grocery lists, etc.). Jumping to future dates is made easy by swiping along the bottom "date carousel," and checking off tasks requires nothing more than a quick tap.
Calvetica is a super quick and simple calendar app with nice contrasting colors and use of Helvetica. Adding an event is easy and can be done with just two taps (compared to 6 taps on the iPhone's built-in calendar). Adding a alarm reminder requires just a couple more taps and because Calvetica syncs to the iPhone's built-in calendar database, you can use both in conjunction. For instance, I like using Calvetica to add events and view my day-to-day appointments, but I still use the built-in calender to manage events. Unfortunately Calvetica can't sync to multiple calendars, so hopefully that's something that will be fixed in v2.
TenPlusTwo is as minimalist as it gets and may come in handy for the hardcore procrastinator. This app is inspired by the (10+2)*5 procrastination hack in which you focus on 10 minutes of work, followed by a mandatory 2 minute break (5 times in concession). The app is nothing more than a bare-bones timer set to those intervals, but its simplicity is pretty refreshing. So if your mind tends to wander the longer you work, following this system may actually help you get things done.