The Neon Museum has started offering evening tours. The evening tours are every half hour from 7pm – 9pm. Tickets are $25 for adults or $22 for seniors, students, NV residents or military personnel. That is $7 more than the regular daytime tour rate, but the addition of the dramatic architectural lighting is worth it. Note that the signs themselves do not light up.
Visit the Neon Museum website for more info and tickets.