Last week, ladyada joined our Community, and several of Adafruit's wonderful Open Source Hardware products are available from Newark element14! Several of the newly added products are ideal for Arduino projects.
I dig Adafruit's handy 8x8 LED matrix modules which come in Green , Yellow and Red . Only two I/O pins are needed to hook these displays up to the Arduino via I2C (plus power and ground). Their great tutorial makes it easy to get started:
These displays can be combined together to make awesome Halloween projects:
They look great animated together:
If you need more inspiration, then checkout the epic e-demon costume by Phil Burgess of Adafruit.
Adafruit's 16x2 character LCD shield kit is a great way to add both a display, pushbuttons and backlight control while saving I/O pins for the rest of your project. It uses the I2C bus just like the 8x8 matrix displays above:
Want to make a data logging project that records time-stamped sensor readings? A Real Time Clock (RTC) can keep time even between power loss, and the DS1307 RTC breakout board is an easy way to add one to an Arduino:
Adafruit's tutorial shows how to assemble the board and provides example Arduino code for retrieving the date and time from the RTC.
Finally, want a low-power, high-contrast display that will make your project standout? Then checkout this blue OLED character display :