Town Monument Blueprints
If you manage to raise your town's Star Level to 5, you will unlock the blueprints for the Town Monument.
Uber-Sims
There are six types of Town Interest, which you can increase by adding items and houses that fit into that nature. If you add enough items to max one of those town interests--make it read 100% on the Status screen--you'll attract an Uber-Sim. The six types of Town Interest are Studious, Spooky, Geeky, Fun, Tasty and Cute. The six Uber-Sims are Samurai Bob, Mel, Star, the Amazing Daryl, Chancellor Ikara and Hopper.
Cheat Keyboard
Press the minus (-) button on your Wii remote to bring up the pause menu. Press the following buttons in rapid succession to bring up a cheat keyboard: 2, 1, down, up, down, up, left, left, right, right. Use the keyboard to type in cheat codes that will unlock special items. Note that all codes are case-sensitive.
Couches
Bring up the Cheat Keyboard and type in the code "T7srhca" and you'll be rewarded with blueprints for a Modern Couch. If you would prefer a sleek-looking Hourglass Couch, type the code "Ghtymba" into the keyboard.
Bed
Using the code "Ahvmrva" rewards you with the plans for the ultra-cool Racecar Bed. Try the Rickshaw Bed with the code "Itha7da." If you want to have friends over, try "F3nevr0" and you'll have a sleepover in your new Bunk Bed.
New Clothes
Bring up the cheat keyboard, and you can fill your wardrobe with some pretty interesting and hard-to-find gear. For example, the code "Gvsb3k1" earns you a Genie Outfit. The code "N10ng5g" will open up some Camouflage Pants, while you could get a White Jacket with "R705aan." For a sparkle, try the Diamond Vest with "Tglg0ca." Or, to match the Rickshaw Bed, you should sleep in a Kimono: use code "I3hkdvs."