Mind like a sieve? Memorising speeches
Divide your speech into sections. As you rehearse each section, choose either a different part of the room or of your body to associate it with. I normally use my fingers. Typically, your speech will have an introduction, three main points and a conclusion and, even with my maths skills I can manage to count to five.
If you get access to your room before the presentation, use the same technique but associate with different parts of the room.
This technique takes some practice and won't replace key cards but it will mean that you have a back up plan and won't be reduce to scrabbling around on the floor for your pages as the audience enjoys the spectacle!