Just one example: How to build a SuGO Bot.
To give you an idea of what's involved with building a SuGO bot, here are the steps required to build "Pushy".

Pushy is a simple "wedge" sumo bot.  He has twin rear wheel drive and a wedge at the front, and each wheel has a single stage gear reduction (8:48) for improved handling.  The RCX "brain" is mounted across the body.

Pushy is a lightweight, weighing in at only 1 lb, 2 1/4 ounces.

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 Although you typically don't know what parts you'll need to build a SuGO 'Bot until you're finished, here's Pushy's parts list.

This is just a tiny sampling of what you can use at a GEARS SuGO event. 

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 First we start with the chassis.  It's made using four 16x Beams. 

We use 8x axles to attach the main drive gears.  A short 4x Beam is used as a space at the front of the robot.

Small 2X connector studs are used to hold all the beams together.  This is a great technique for making a strong 'bot.

Full size spacers are used to hold all the parts on the axle.
The two chassis sides are connected together using two 8x beams and more studs.

The hubs and tyres are connected to the axels and held in place with 1/2 spacers.

Since the hubs are not symmetrical, it's important to align them BOTH with the recessed rims on the outside.

Next we collect the pieces for the motor mounts.  These are two 2x8 plates, and two 1x8 plates.

We also collect two 2x4 ramps for the wedge and the light sensor and right-angle attachment bracket.

Note that the wires exit the light sensor at the same end that has the studs of the mounting bracket.
The motor mount is attached at the rear of the robot, creating two raised strips to support the motors.

The ramps are attached under the front of the chassis and the light sensor is mounted to the center of the chassis with the wired facing up.
  With the 'bot flipped over, we can collect and mount the body of the wedge structure.

The 8x2 ramp is used to extend the wedge, and the 2x8 and 2x10 blocks are used to extend it backwards.

The small 2x1 block is placed behind the light sensor to provide some extra support.
Two more 2x4 blocks and a 2x10 block are added to fill out the wedge.
Here we see the completed underside of the 'bot. 

The large flat surface enables the light sensor to detect the white line and still have plenty of time to reverse the robot.
The 'bot is flipped upright again, and the parts collected for the motor drive.

Two tiny cogs will be attached to the motor drive shaft to engage with the wheel drive gear.

The motors mount firmly on the motor supports and the small gear should cleanly engage the larger gear.

2x4 plates are also collected to be used to brace the front of the chassis.  Plates are another great way to add strength or stability without taking up a lot of room.  One plate is 1/3 the thickness of a standard block.

 
The parts are now collected for the motor retaining clips and eye bracket.

The motor clips will be mounted on top of a 2x8 block and slide into slots at the front of each motor.  This will prevent the motor from lifting odd the chassis in moments of battle.

Two more right angle brackets and a 2x8 plate form the eyes mount.  The brackets are place on top of the plate with the bracket studs pointing forwards.  These will be used to hold the eyes assembly
Collect the two cables for the motors and more 2x8 blocks to fill in the bed of the chassis.

A 2x8 plate is used to anchor the motors together once their cables have been added.

Make sure the motor cables extend out the back of the robot.
  Lat to be added are the eyes and the RCX Brain.

Two 2x8 blocks are attached to the bottom of the RCX to stand it up of the chassis bed.

A 2x8 plate with two 2x1 plates are used to mount the eyes to the upright brackets.  Note that the eyes are attached so that the connector is on the right side of the robot (looking forward).  This will ensire that left and right are not reversed
Clamp the RCX down onto the chassis and add the eyes to the front.

Make sure you run the cable from the light sendor, up and begind the eyes.  You don't want Pushy seeing the cable and thinking that it's another robot.
Here is a top view of the completed robot.

The light sensor is plugged into Input 1, and the Eyes are plugged into input 2.

The left and right motor are plugged into Motor outputs A and B respectively.

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Here is a front view of the completed robot.

What about some ideas for improvement?

How about a wider wedge, or what about a motorized lifter at the front, or maybe more weight for extra traction, or wider wheels and more gear reduction..

The sky's the limit.  .... well, not really..... it still has to weight less than 1 lb, 8 oz, but there's LOTS of room for new ideas and funky attachments.