Any fun project.

I am a beginner to arduino and I have already made a simple two wheeled robot, a clock using motors and paper, and so on.

Please tell me some fun projects which I can make using the following stuff:

LEDs
Resistors
IR obstacle sensor
Ultrasound sensor
motors
Arduino UNO

And I bought a IR obstacle sensor with a photo diode and a white led in front of it. How can I use it?
It has 3 terminals OUT, V and GND. Where do I have to connect these terminals?

Add on to the robot to make it move around and avoid obstacles it detects with the sensors.
LEDs can be lit up as it goes as progress indicators.
IR sensor - do you have a part number, a picture of it, some kind of clue you can share?

I bought it from here:
http://www.amazon.in/ELEMENTZ-INFRARED-PROXIMITY-OBSTACLE-SELECTION/dp/B00MBXTA0A/ref=sr_1_1?ie=UTF8&qid=1419686326&sr=8-1&keywords=ir+obstacle+sensor+arduino

Amazon link is not too helpful with info.
Can you read any markings on the chip?

The titile & description...

ELEMENTZ IR INFRARED PROXIMITY / OBSTACLE DETECTOR SENSOR MODULE with HIGH / LOW OUTPUT MODE SELECTION - FOR RASPBERRY PI, ARDUINO, AVR, PIC, 8051

suggest the output is digital, can be set active high or active low and the trim pot will adjust the activation threshold.

GND goes to GND on your arduino.
V goes to 5V pin on arduino.
OUT goes to one of your digital pins.

A line-following robot. You will need to mount at least a couple of ir sensors at the front of your 2 wheel robot. These will point down to detect a line drawn on the floor. Start with a simple oval racing car track and see if you can get the robot to steer around it successfully. Then try a figure of 8 track.

Paul

Please tell me some fun projects which I can make using the following stuff:

You might try a walking biped project.

http://davidbuckley.net/DB/A_Minimalist_Approach_to_Biped_Walking.htm#BFphotos