Here is a simple looping timer bash script that plays a nice singing bowl sound using mplayer.  You run the script as follows:

timer.sh TIME

Where time is specified according to the sleep manual. For example, a 5 minute timer would be:

timer.sh 5m

function timer(){
#!/bin/bash
while sleep $1; do
 mplayer -af volume=20:0 /home/user/2166__suburban-grilla__bowl-struck.wav
done
timer
}

timer $1

Make sure you update the script to the location of the singing bowl, or whatever else sound you want to hear at each interval.

It currently does not display the remaining time. For a future release.