The snow centre in hemel hempstead in hertfordshire is an indoor ski slope with actual snow. Throughout january theyre doing ski or snow board all day for £29 adults or £23 children, this includes equipment.
You have to be able to control your speed and turns so not suitable for begginners but they have lessons available for that.
Monday - Friday 9am-5pm ski all day
For the weekends they also day ski for 3 hours sat / sun after 5pm for £30.
There is a cafe / resteraunt on site to break up the time. Location is just off the M1 and not far from the m25. Great way to spend a day improving technique or warming up for a winter holiday if you ask me!