Kids can now learn to tell time faster and easier with the many free interactive teaching clocks and games on the web. I've seen what a difference 15 minutes on a game makes compared to 15 minutes on a telling time worksheet. Children are more engaged, get much more practice, and a truckload of immediate positive feedback. Their test scores improve and it does wonders for their self-confidence (not to mention the time you save from answering the what-time-is-it questions).
There's a broad variety of clock games for different skill levels. Some are starter clocks where kids practice telling time to the hour. Others teach them to tell time in 30-minute, 15-minute, 5-minute and 1-minute increments. Some games challenge them to calculate lapsed time - a skill some much older students are still trying to master. I've described seven of my favorite on my Squidoo post Interactive Telling Time Games and Clocks. Give them a whirl - remember, it's free. And see if you can get your kid's teacher to toss the telling time worksheets!