Tardis-space and tardis-time are two useful approaches that I've been experimenting with.
Tardis-space, put simply, is when an area is bigger on the inside than the outside. Thus the area can contain more things - objects, people etc - than is apparent from the 'outside'. The tardis-space can be within an object but it can also be in any area of space.
Tardis-space is useful when cloning aspects. For example, I may imagine a PC monitor with a thousand screens. Because of tardis-space these screens can be superimposed over the actual screen and thus the screen area contains a thousand screens. Then I can begin to think of purposes/functions for each of the screens. Considering one of the screens as a 'filter' for words led to these ideas:
Learning a new language by gradually replacing words as you surf
and considering how one of the screens could have a 'recording' function led to the idea of a PC facility that records ALL screen activity, so that the user can review all their activity online at the end of the day or at some time in the future. This would be a useful tool for training departments. Perhaps trainees could review their day's learning from home at a later date? This would also be good for parents who would like to know their children are safe-surfing when using the internet.
Tardis-time is a similar idea to tardis-space but uses time instead of space. It could be said that chunks of time could be inserted into an event/activity etc. The chunks of time can be of any duration and the important point is that the subsequent events remain unaffected.
If an event was filmed and the frames were viewed on celluloid then time could be inserted between any two frames and the subsequent frames would remain unaffected. So if the event was over six frames:
A B C D E F
then 'time' could be inserted between C and D and the subsequent frames (and thus events) of E F would remain unchanged.
In the example of a child birth:
A = arrival at maternity unit
B = child is born
C = doctor holds child
D = doctor gives child to mother
E = mother says 'aw'
F = mother goes home
Inserting a tardis-time of one hour between C and D I considered what events could occur. (Naturally the concept of tardis-time ensures that E and F are unaffected.) I thought of this idea:
Two 'twins' for each newborn baby
Analysing many films (for my 'automatic fiction' project) I've noticed that a sizeable number of events in any film can be viewed as 'time-tardis inserts' where the inserted events actually have no effect on subsequent events.