Actually, the Bible says absent from the body, present with the lord. If you die tomorrow, you will be in heaven tomorrow.
This "sleep" nonsense is a new invention in Christianity.
I don't think it's nonsense at all. I think you need a body in order to be conscious- as a human being. So dead, without a body, we go offline, like a piece of software being taken out of a computer. But when our hardware gets upgraded, and our spirits again have a new body through which to express itself, we come back online, and to the individual, no time would have passed. I think the sleep metaphor is for the living, to help us understand something that happens in timelessness. If you were to die tonight, as a Christian, your eyes would close, and then immeadiately seem to open in your new body, at the rapture. Several years or decades may have passed, (by earth's reckoning).
It is not nonsense. For those dead in Christ, they have yet to receive a glorified body which will occur at the Rapture of the Church. Believers who have died in Christ are said to be asleep in Jesus. I Thess. 4:13-16