If your iPad will not turn on or wake up, the battery is probably out of power and needs to be recharged. Try charging the iPad for at least 10-20 minutes and see if it springs to life. If it is still out of commission after even an hour or so, you will need to try restarting, resetting, updating and restoring the device in that order as Apple recommends. If it still won't turn on, you may have a hardware problem. It is most likely a dead or weak battery, but it could be a display problem or your battery might need replacing.
If your iPad will not turn off, you will need to try resetting it or force quitting a misbehaving app. If that won't work, or the iPad is unresponsive, let the battery drain until it runs out of power and then recharge it. This may solve the problem on its own or you may need to try restoring the device. Please note that restoring the iPad will erase all data. Be sure that you have recently backed up your iPad before restoring it.