To load the scripts:
1. Start Reaper
2. Press F4 for the actions dialogue
3. Tab until you get to the New Action button
4. Press shift space and a context menu appears.  Arrow down to Load Script.
5. An open dialogue appears where you can browse and select a LUA script file

To use the script:
1. In a Reaper project place a section of audio onto a track.
2. Set the grid size you want e.g. Control Shift number 4 on top row sets to quarter notes, control shift 3 sets to 32nd note grid divisions 
3. Select the item of audio by going to the track and using control left or right arrow
4. Press F4 to get the actions dialogue
5. Type something like "split odd" or "split even" and arrow down to select the script you want.  Hit enter to run it.

The selected item will get split at grid divisions and then alternate ones deleted.  The script with even in its name deletes even numbered items and this is the most likely one to use.  It keeps the first, deletes the second, keeps the third, deletes the fourth, and so on.  The odd script deletes odd numbered items.

There will be many more items on your track now and playing them will give interesting results.  It is a good idea to have a default fade in and fade out to avoid clicking sounds.  Set this in Preferences  and the Default Media Settings item.  A value of 0.003 seconds works quite well.

This effect is useful as a special effect a bit like a stutter.

The script will split all items selected at the time it is run even across tracks so ensure you have only the items you want to split selected.