E ride nights no longer exist. They have been replaced by Extra Magic Hours (the evening version).
The E ride nights were exclusive to Magic Kingdom. It was nights when specific attractions at MK would be open for 3 extra hours for resort guests only but you had to already have park admission and pay an additional fee for them (around $12 per person) they also put a limit on how many tickets were sold.
Disney decided that it would be a better benefit to the resort guests to offer evening extra magic hours at all the parks. EMH used to be just a morning offering one hour before park opening at a different park each day and then the E ride was exclusive to MK on certain nights. The new way is that each park has a morning (one hour before park opens) and an evening (3 hours after park close) Extra Magic Hour throughout the week, where certain rides will be open. They are no additional charge (although you have to have a park ticket to attend) and they do not limit the entrance, any WDW resort guest with a park ticket can participate.