Tired of prank SMSes. Need a simple way to block them, and keep your inbox clean? Don't worry. You got it! SMS Firewall is a simple and cute (hope you like it!) Android application to block and quarantine unwanted SMS from reaching your inbox. Unwanted are those who are neither in your contacts list nor in the allowed list, which is provided by the application. Phone numbers or sender names such as your bank or mobile service provider can be added to the allowed list. You got an option to either notify you of the blocked SMS or ignore it, in which case you will have check the quarantine vault by yourself. Besides, you have a 'Just Monitor' mode, which is primarily used for debugging purposes or when you don't want to block SMS from unknown sender(s) (for a while). When this mode is switched on, SMS from unknown senders will reach the inbox and also a copy of it is saved in the quarantine vault. Here are a few screen shots to get you attracted...
Another effective [debugging] technique is to explain your code to someone else. This will often cause you to explain the bug to yourself. Sometimes it takes no more than a few sentences, followed by an embarrassed "Never mind. I see what's wrong. Sorry to bother you." This works remarkbly well; you can even use non-programmers as listeners. - From "The Practice of Programming" by Brian W Kernighan & Rob Pike.