If you've got an Elgato EyeTV box, and the latest software (1.8.4) try this: hold down control when you select 'Open Live TV Window', and select a channel. Do it again. and again. and again
Yup, you can now view and record multiple channels !!! It does depend on the hardware you have, and the channel setup, but wow - what a freebie !! Excellent stuff.