diff --git a/src/Utils/Schedule/Week.hs b/src/Utils/Schedule/Week.hs
index 0ac761659..852b55fa1 100644
--- a/src/Utils/Schedule/Week.hs
+++ b/src/Utils/Schedule/Week.hs
@@ -87,15 +87,15 @@ weekSchedule uid dayOffset = do
       in \case
         ScheduleCourseEvent{sceOccurrence} -> occurrenceIsInSlot sceOccurrence
         ScheduleTutorial{stOccurrence}     -> occurrenceIsInSlot stOccurrence
-        ScheduleExamOccurrence{seoStart}   -> let slotTime     = timeSlotToUTCTime tz day  slot
-                                                  nextSlotTime = timeSlotToUTCTime tz day (slot+slotStep)
+        ScheduleExamOccurrence{seoStart}   -> let slotTime     = timeSlotToUTCTime tz day slot
+                                                  nextSlotTime = timeSlotToUTCTime tz day $ nextTimeSlot slot
                                               in slotTime <= seoStart
                                                  && seoStart < nextSlotTime
     
     events' :: Map Day (Map TimeSlot [ScheduleEntry])
     events' = Map.fromList $ week <&> \day ->
       ( day
-      , Map.fromList $ slotsToDisplay <&> \slot ->
+      , Map.fromList $ timeSlotsToDisplay <&> \slot ->
         ( slot
         , filter (seIsInSlot day slot) $ join $
                     (courseEventToScheduleEntries  <$> courseEvents)
@@ -144,6 +144,10 @@ weekSchedule uid dayOffset = do
               | otherwise = go $ pred day
             firstDay = toEnum $ fromEnum Monday + fromInteger (fromMaybe 0 dayOffset)
 
+    -- TODO: make configurable
+    timeSlotsToDisplay :: [TimeSlot]
+    timeSlotsToDisplay = timeSlot <$> [8,10..18]
+
   $(widgetFile "widgets/schedule/week")
 
 
diff --git a/src/Utils/Schedule/Week/TimeSlot.hs b/src/Utils/Schedule/Week/TimeSlot.hs
index 72afb0a10..eb811c7fb 100644
--- a/src/Utils/Schedule/Week/TimeSlot.hs
+++ b/src/Utils/Schedule/Week/TimeSlot.hs
@@ -1,5 +1,8 @@
 module Utils.Schedule.Week.TimeSlot
-  ( TimeSlot, firstSlot, lastSlot, slotStep, slotsToDisplay, isInTimeSlot
+  ( TimeSlot(..)
+  , timeSlot
+  , isInTimeSlot
+  , nextTimeSlot
   , timeSlotToUTCTime
   , formatTimeSlotW
   ) where
@@ -9,31 +12,37 @@ import Import
 import Handler.Utils.DateTime (formatTimeRangeW)
 
 
--- TODO: very temporary slot representation, WORK IN PROGRESS
--- TODO: include UTCTime stamps for begin and end (end timestamp excluded)
-type TimeSlot = Int
-
-firstSlot, lastSlot, slotStep :: TimeSlot
-firstSlot = 8
-lastSlot = 18
+slotStep :: Int
 slotStep = 2
 
-slotsToDisplay :: [TimeSlot]
-slotsToDisplay = [firstSlot,firstSlot+slotStep..lastSlot]
+
+data TimeSlot = TimeSlot
+                { tsFrom :: TimeOfDay
+                , tsTo   :: TimeOfDay  -- end excluded
+                }
+                deriving (Eq, Ord, Show, Read, Generic, Typeable)
+
+timeSlot :: Int -> TimeSlot
+timeSlot h = TimeSlot{..} where
+  tsFrom   = TimeOfDay  h           0 0
+  tsTo     = TimeOfDay (h+slotStep) 0 0
 
 
 -- | Check whether a given time of day lies within a given time slot
 isInTimeSlot :: TimeOfDay -> TimeSlot -> Bool
-isInTimeSlot time slot = TimeOfDay slot 0 0 <= time && time < TimeOfDay (slot+slotStep) 0 0
+isInTimeSlot time TimeSlot{..} = tsFrom <= time && time < tsTo
+
+-- | Get the successor of a time slot
+nextTimeSlot :: TimeSlot -> TimeSlot
+nextTimeSlot TimeSlot{tsTo=tsFrom} = let tsTo = TimeOfDay (todHour tsFrom + slotStep) 0 0 in TimeSlot{..}
 
 -- | Convert a TimeSlot to UTCTime for a given TimeZone
 timeSlotToUTCTime :: TimeZone -> Day -> TimeSlot -> UTCTime
-timeSlotToUTCTime tz day slot = UTCTime{..} where
+timeSlotToUTCTime tz day TimeSlot{..} = UTCTime{..} where
   utctDay     = slotDayOffset `addDays` day
   utctDayTime = timeOfDayToTime slotTimeOfDay
-  (slotDayOffset, slotTimeOfDay) = localToUTCTimeOfDay tz $ TimeOfDay slot 0 0
+  (slotDayOffset, slotTimeOfDay) = localToUTCTimeOfDay tz tsFrom
 
--- TODO: refactor in progress
 -- | Format a given TimeSlot t as time range from t until the next TimeSlot
 formatTimeSlotW :: TimeSlot -> Widget
-formatTimeSlotW slot = formatTimeRangeW SelFormatTime (TimeOfDay slot 0 0) $ Just $ TimeOfDay (slot+slotStep) 0 0
+formatTimeSlotW TimeSlot{..} = formatTimeRangeW SelFormatTime tsFrom $ Just tsTo
diff --git a/templates/widgets/schedule/week.hamlet b/templates/widgets/schedule/week.hamlet
index 477482f01..678245e11 100644
--- a/templates/widgets/schedule/week.hamlet
+++ b/templates/widgets/schedule/week.hamlet
@@ -9,7 +9,7 @@ $newline never
           <th .table__th uw-hide-column-header=#{dayTableHeadIdent day}>
             ^{formatTimeW SelFormatDate day}
     <tbody>
-      $forall slot <- slotsToDisplay
+      $forall slot <- timeSlotsToDisplay
         <tr .table__row>
           <td .table__td>
             ^{formatTimeSlotW slot}