See
Tablook.com.
I wanted to put all interesting bitcon-related information in one table for convenient look-up. But new coins/exchanges/mining pools and other data sources keep popping up every day, so instead of displaying some fixed information, I threw a JavaScript interpreter and editor in, so user can write her own scripts to download and format information in any way possible. You can display difficulty projections, mining profitability calculations, exchange rates, or any other data available on the internet. Share scripts with others, and search for scripts that others created - kinda micro app store.
Examples of scripts that I created:
btc_bitstamp - Last bitcoin price at Bitstamp
btc_bitfinex - Last bitcoin price at Bitfinex
kraken_polo_eth_btc_arb - watch for ETH arbitrage opportunities between Kraken and Poloniex
btc_difficulty - show current bitcoin difficulty and projected increase
eth_btc_polniex - ETH/BTC exchange rate at poloniex
fx_eurusd - obvious
datetime - current time
Scripts can also vibrate the phone and show notifications, in case you want to be notified when BTC crosses $10000 level (soon I hope!).
I even wrote a script to show next bus arrival time for my local bus route.
App is available in Google Play Store
https://play.google.com/store/apps/details?id=com.tablook1.tablook.
Can make an iPhone version if there is any interest.